Organotin adducts with pyrimidinethione: crystal structure of dimethyldi(pyrimidine‐2‐thiolato)tin(IV) and diphenyldi(pyrimidine‐2‐thiolato)tin(IV)

The complexes dimethyldi(pyrimidine‐2‐thiolato)tin(IV) ( 1 ) and diphenyldi(pyrimidine‐2‐thiolato)tin(IV) ( 2 ) have been structurally ­characterized by means of X‐ray crystallography. Complex 1 exhibits strong π–π stacking interactions and adduct 2 is self‐assembled via intermolecular hydrogen bonds, C H–π and π–π stacking interactions. Partial solvolysis occurs in organic solvents for 1 and 2 . Copyright © 2000 John Wiley & Sons, Ltd.     

Specific Noncovalent Association of Chiral Large‐Ring Hexaimines: Ion Mobility Mass Spectrometry and PM7 Study

Ion mobility mass spectrometry and PM7 semiempirical calculations are effective complementary methods to study gas phase formation of noncovalent complexes from vaselike macrocycles. The specific association of large‐ring chiral hexaimines, derived from enantiomerically pure trans‐1,2‐diaminocyclohexane and various isophthaldehydes, is driven mostly by CH–π and π–π stacking interactions. The isotrianglimine macrocycles are prone to form two types of aggregates: tail‐to‐tail and head‐to‐head (capsule) dimers. The stability of the tail‐to‐tail dimers is affected by the size and electronic properties of the substituents at the C‐5 position of the aromatic ring. Electron‐withdrawing groups stabilize the aggregate, whereas bulky or electron‐donating groups destabilize the complexes.     

Synthesis and Self‐Assembly of Novel s‐Tetrazine‐Based Gelator

The design, synthesis and self‐assembly of new symmetrical 3,6‐bis(4‐(3,4,5‐tris(dodecyloxy)benzoate)phenyl)‐1,2,4,5‐tetrazine were described. The novel gelator, sym‐tetrazine, was prepared by addition reaction of 4‐cyanophenol with hydrazine monohydrate followed by oxidation reaction to afford the corresponding 3,6‐bis(4‐hydroxyphenyl)‐1,2,4,5‐tetrazine which was then subjected to esterification reaction with 3,4,5‐tris(dodecyloxy)benzoic acid. The chemical structure of the sym‐tetrazine gelator was confirmed by elemental analysis, fourier‐transform infrared spectroscopy (FT‐IR), and nuclear magnetic resonance (¹H‐ and ¹³C‐NMR) spectral measurements. It was confirmed to exhibit relatively strong gelation ability to produce supramolecular assemblies in several polar alcoholic organic solvents, such as butanol, octanol, and 1,6‐dihydroxyhexane. The π‐π stacking and van der Waals mediated self‐assembly of tetrazine‐based organogelator were studied by scanning electron microscopy images of the xerogel to reveal that the obtained organogel consists of fibrillar aggregates. Investigation of FT‐IR and concentration‐dependent ¹H‐NMR spectra confirm that the intermolecular van der Waals interactions and π‐π stacking were the key driving forces for self‐assembly during gelation process of s‐tetrazine molecules.     

Columnar Mesophase Formation of Cyclohexa‐m‐phenylene‐Based Macrocycles

Two novel discotic macrocycles, substituted cyclohexa‐m‐phenylene (CHP) and cyclo‐3,6‐trisphenanthrylene (CTP), and the linear oligomer 3,3′:6′,3′′‐terphenanthrene (TP) as a model substance have been synthesized by repetitive cross‐coupling reactions. To correlate the molecular design with the supramolecular architecture and the established macroscopic order, 2D wide‐angle X‐ray scattering experiments were performed on mechanically extruded filaments. At room temperature in their crystalline phases, all three compounds revealed columnar assemblies in which the macrocycles self‐organized by π‐stacking interactions. The degree of macroscopic order was found to depend upon the planarity and stiffness of the aromatic core. The flexible CHP ring showed a poor macroscopic order of the columnar structures and a low isotropization temperature, whereas the more‐planar, less‐flexible CTP self‐assembled into well‐defined superstructures. The larger π‐stacking area and the more‐pronounced intermolecular interactions for CTP led to the formation of a mesophase over a very large temperature range. The surprising columnar organization of the “open” TP system was explained by back‐folding of the molecule into a ringlike structure.     

p‐Quaterphenylene as an Aggregation‐Induced Emission Fluorogen in Supramolecular Organogels and Fluorescent Sensors

Two dumbbell‐shaped organogelators with a p ‐quaterphenylene core were synthesized, and their self‐assembly properties were investigated. These low‐molecular‐weight gelators could form self‐supporting gels in many apolar organic solvents with an H‐type aggregation form through a synergic effect of π–π stacking, intermolecular translation‐related hydrogen bonding, and van der Waals forces. In comparison to the p ‐terphenylene‐cored gelator, the extended π‐conjugated segment improved the gelation efficiency significantly with enhanced gelation rate. Additionally, these p ‐quaterphenylene‐centered gelators exhibited strong fluorescence emission induced by aggregation, which not only provided an in situ method to optically monitor the gelation process, but also endowed these self‐assemblies with substantial applications in sensing explosives.     

Fully and partially fluorinated flavone derivatives

In the crystal structures of the fully and partially fluorinated flavone derivatives 5,6,7,8‐tetrafluoro‐2‐(2,3,4,5,6‐pentafluorophenyl)‐4H‐1‐benzopyran‐4‐one, C₁₅HF₉O₂, (I), and 5,6,7,8‐tetrafluoro‐2‐phenyl‐4H‐1‐benzopyran‐4‐one, C₁₅H₆F₄O₂, (II), the pentafluorophenyl group and the pyranone moiety in (I) are twisted due to repulsion of the F substituents, and a CO(δ⁻)...π(δ⁺) intermolecular interaction is observed between the carbonyl O atom and the pentafluorophenyl group. In (II), on the other hand, the phenyl group and the pyranone moiety are almost coplanar, and arene–perfluoroarene interactions are observed in the head‐to‐tail intermolecular columnar stacking between the phenyl group and the tetrafluorophenylene moiety.     

Water‐Regulated Self‐Assembly Structure Transformation and Gelation Behavior Prediction Based on a Hydrazide Derivative

Herein, we report the water‐regulated supramolecular self‐assembly structure transformation and the predictability of the gelation ability based on an azobenzene derivative bearing a hydrazide group, namely, N‐(3,4,5‐tributoxyphenyl)‐N′‐4‐[(4‐hydroxyphenyl)azophenyl] benzohydrazide (BNB‐t4). The regulation effects are demonstrated in the morphological transformation from spherical to lamellar particles then back to spherical in different solvent ratios of n‐propanol/water. The self‐assembly behavior of BNB‐t4 was characterized by minimum gelation concentration, microstructure, thermal, and mechanical stabilities. From the spectroscopy studies, it is suggested that gel formation of BNB‐t4 is mainly driven by intermolecular hydrogen bonding, accompanied with the contribution from π–π stacking as well as hydrophobic interactions. The successfully established correlation between the self‐assembly behavior and solubility parameters yields a facile way to predict the gelation performance of other molecules in other single or mixed solvents.     

Construction of Alkynylplatinum(II) Bzimpy‐Functionalized Metallacycles and Their Hierarchical Self‐Assembly Behavior in Solution Promoted by Pt⋅⋅⋅Pt and π–π Interactions

A family of new alkynylplatinum(II) 2,6‐bis(benzimidazol‐2′‐yl)pyridine (bzimpy)‐functionalized supramolecular metallacycles with different shapes and sizes have been successfully prepared by coordination‐driven self‐assembly. The obtained metallacycles showed switchable emission and a strong tendency to form intermolecular Pt???Pt and π–π stacking interactions in solution that were not displayed by their individual precursors. Further investigation revealed that the existence of the metallacyclic scaffold at the core could facilitate the formation of intermolecular Pt???Pt and π–π stacking interactions of peripheral alkynylplatinum(II) bzimpy units. Moreover, the shapes and sizes of the metallacyclic scaffold have a significant influence on the hierarchical self‐assembly behavior. Among the three metallacycles, hexagonal metallacycle A , with a relatively small size, could spontaneously self‐assemble into an aromatic guest stimuli‐responsive metallogel at room temperature without a heating–cooling process.     

Shape‐Persistent (Pt‐salphen)2 Phosphorescent Coordination Frameworks: Structural Insights and Selective Perturbations

The development of molecular frameworks derived from binuclear platinum(II) aromatic Schiff base (salphen) complexes and their supramolecular chemistry have been undertaken. A series of axially rotating (Pt‐salphen)₂ luminophores, tethered in a cofacial manner by a rigid linker (xanthene, 1 ; dibenzofuran, 2 ; biphenylene, 3 ), was synthesized in which the O(salphen) groups are potentially amenable for guest‐binding. The molecular structures of 1 and 3 have been determined by X‐ray crystallography, revealing intra‐ and intermolecular π‐stacking interactions, as well as contrasting syn ( 1 ) and anti ( 3 ) configurations, for the (Pt‐salphen)₂ moiety. All complexes are luminescent in solution at room temperature. Their photophysical and solvatochromic properties have been examined, and the emissions are assigned to mixed triplet O(p)/Pt(d)→π*(diimine) excited states. The red‐shifted fluid emissions and lower quantum yields of 1 and 3 , relative to 2 , are ascribed to enhanced intramolecular π‐stacking interactions. Photophysical changes and selective responses to metal ions (particularly Pb²⁺) have been investigated by using various spectroscopic methods and DFT calculations, and through comparative studies with control complexes. A plausible binding mechanism is proposed based on occupation of the O(salphen)‐binding cavity, which induces perturbation of intramolecular π–π interactions, and hence the self‐quenching and emission properties, of the (Pt‐salphen)₂ unit.     

Effect of Alanine and Glycine on the Assembly of Surfactant‐like Peptides with Tyrosine as Hydrophilic Head in Basic Solution

Surfactant‐like peptides (SLPs ) can self‐assemble into various nanostructures, which have shown great potential for a variety of biomedical and biotechnological applications. In this work, two SLPs , V₄Y , and V₄AGY , were designed and synthesized, both of which had hydrophobic head valines (V) with large side‐chain steric hindrance effect and the hydrophilic head tyrosine (Y) with a rigid ring and two negative charges in the basic solution. Fourier transform infrared and circular dichroism studies confirmed their different secondary structures, whereas atomic force microscopy and dynamic light scattering characterized the difference in their morphologies. In solution, they formed different secondary structures. Correspondingly, V₄Y and V₄AGY formed noncompact spherical aggregates and a spiral clubbed structure, respectively. In V₄AGY , the introduction of alanine (A) and glycine (G) increased the molecule's flexibility and increased the distance between the tyrosine and four continuous valines, so as to weaken the synergistic action of electronic repulsion and steric hindrance and strengthen the intermolecular hydrogen bond beneficial to β‐sheet formation and the axial growth of the self‐assembly. Therefore, the flexibility of the molecule and the side‐chain steric effect of the two heads of SLPs are non‐negligible in the tuning process of peptide self‐assembly, in addition to hydrogen‐bonding, hydrophobic, and electrostatic interactions.     

The structure‐dependent self‐association of five phenolic acids in aqueous solution

Weak self‐interaction plays an important role in interpreting the biomechanisms and modes of drug action. The structure‐dependent self‐association of five phenolic acids with various bioactivities, including danshensu (DSS), caffeic acid (CA), rosmarinic acid (RA), lithospermic acid (LA), and salvianolic acid B (SA), was investigated by ¹H NMR. These phenolic acids have similar condensed structures, with a CA moiety and varying numbers of DSS moieties. The strengths of the self‐association constants are in the order DSS < CA < RA < LA < SA, which corresponds to the increasing molecular size of these phenolic acids and roughly corresponds to the increasing number of DSS moieties. The binding site for the self‐aggregation of these phenolic acids has been identified to be on the CA moiety, rather than on the DSS moiety, as a result of CA's stronger aromatic π–π interactions, which cause larger chemical shift variations. The thermodynamic parameters for the self‐association of these phenolic acids show that the self‐association is spontaneous and enthalpically favorable at room temperature in all cases. It was inferred that π–π interactions and intermolecular hydrogen bonding stabilize the stacking structures of the phenolic acids. Knowledge of self‐association processes will enable us to quantitatively assess the possible effects of self‐aggregation on the interaction between drug and protein. Copyright © 2014 John Wiley & Sons, Ltd.     

From Intramolecular (Circular) in an Isolated Molecule to Intermolecular Hole Delocalization in a Two‐Dimensional Solid‐State Assembly: The Case of Pillarene

To achieve long‐range charge transport/separation and, in turn, bolster the efficiency of modern photovoltaic devices, new molecular scaffolds are needed that can self‐assemble in two‐dimensional (2D) arrays while maintaining both intra‐ and intermolecular electronic coupling. In an isolated molecule of pillarene, a single hole delocalizes intramolecularly via hopping amongst the circularly arrayed hydroquinone ether rings. The crystallization of pillarene cation radical produces a 2D self‐assembly with three intermolecular dimeric (sandwich‐like) contacts. Surprisingly, each pillarene in the crystal lattice bears a fractional formal charge of +1.5. This unusual stoichiometry of oxidized pillarene in crystals arises from effective charge distribution within the 2D array via an interplay of intra‐ and intermolecular electronic couplings. This important finding is expected to help advance the rational design of efficient solid‐state materials for long‐range charge transfer.     

Complementary Hydrogen Bonding Modulates Electronic Properties and Controls Self‐Assembly of Donor/Acceptor Semiconductors

A comprehensive investigation of the complementary H‐bonding‐mediated self‐assembly between dipyrrolo[2,3‐b:3′,2′‐e]pyridine (P2P) electron donors and naphthalenediimide/perylenediimide (NDI/PDI) acceptors is reported. The synthesis of parent P2P and several aryl‐substituted derivatives is described, along with their optical, redox, and single‐crystal packing characteristics. The dual functionality of heteroatoms in the P2P/NDI(PDI) assembly, which act as proton donors/acceptors and also contribute to π‐conjugation, leads to H‐bonding‐induced perturbation of electronic levels. Concentration‐dependent NMR and UV/Vis spectroscopic studies revealed a cooperative effect of H‐bonding and π–π stacking interactions. This H‐bonding‐mediated co‐assembly of donor (D) and acceptor (A) components leads to a new charge‐transfer (CT) absorption that can be controlled throughout the visible range. The electronic interactions between D and A were further investigated by time‐dependent DFT, which provided insights into the nature of the CT transition. Electropolymerization of difuryl‐P2P afforded the first conjugated polymer incorporating H‐bonding recognition units in its main chain.     

Self‐Assembly of Carboxylic Acid Appended Naphthalene Diimide Derivatives with Tunable Luminescent Color and Electrical Conductivity

Self‐assembly of a series of carboxylic acid‐functionalized naphthalene diimide (NDI) chromophores with a varying number (n=1–4) of methylene spacers between the NDI ring and the carboxylic acid group has been studied. The derivatives show pronounced aggregation due to the synergistic effects of H‐bonding between the carboxylic acid groups in a syn–syn catemer motif and π stacking between the NDI chromophores. Solvent‐dependent UV/Vis studies reveal the existence of monomeric dye molecules in a “good” solvent such as chloroform and self‐assembly in “bad” solvents such as methylcyclohexane. The propensity of self‐assembly is comparable for all samples. Temperature‐dependent spectroscopic studies show high thermal stability of the H‐bonding‐mediated self‐assembled structures. In the presence of a protic solvent such as MeOH, self‐assembly can be suppressed, suggesting a decisive role of H‐bonding, whereas π stacking is more a consequence of than a cause for self‐assembly. Syn–syn catemer‐type H‐bonding is supported by powder XRD studies and the results corroborate well with DFT calculations. The morphology as determined by AFM is found to be dependent on the value of n; with increasing n, the morphology gradually shifts from 2D nanosheets to 1D nanofibers. Emission spectra show sharp emission bands with relatively small Stokes shifts. In addition, a rather broad emission band is observed at longer wavelengths because of the in situ formation of excimer‐type species. Due to such a heterogeneous nature, the emission spectrum spans almost the entire red–green–blue region. Depending on the value of n, the ratio of intensities of the two emission bands is changed, which results in a tunable luminescent color. Furthermore, in the case of n=1 and 3, almost pure white light emission is observed. Time‐resolved photoluminescence spectra show a very short lifetime (a few picoseconds) of monomeric dye molecules and biexponential decays with longer lifetimes (on the order of nanoseconds) for aggregated species. Current–voltage measurements show electrical conductivity in the range of 10^?4 S cm^?1 for the aggregated chromophores, which is four orders of magnitude higher than the value for a structurally similar NDI control molecule lacking the H‐bonding functionality.     

Enzyme Instructed Self‐assembly of Naphthalimide‐dipeptide: Spontaneous Transformation from Nanosphere to Nanotubular Structures that Induces Hydrogelation

Understanding the structure‐morphology relationships of self‐assembled nanostructures is crucial for developing materials with the desired chemical and biological functions. Here, phosphate‐based naphthalimide (NI) derivatives have been developed for the first time to study the enzyme‐instructed self‐assembly process. Self‐assembly of simple amino acid derivative NI‐Yp resulted in non‐specific amorphous aggregates in the presence of alkaline phosphatase enzyme. On the other hand, NI‐FYp dipeptide forms spherical nanoparticles under aqueous conditions which slowly transformed into partially unzipped nanotubular structures during the enzymatic catalytic process through multiple stages which subsequently resulted in hydrogelation. The self‐assembly is driven by the formation of β‐sheet type structures stabilized by offset aromatic stacking of NI core and hydrogen bonding interactions which is confirmed with PXRD, Congo‐red staining and molecular mechanical calculations. We propose a mechanism for the self‐assembly process based on TEM and spectroscopic data. The nanotubular structures of NI‐FYp precursor exhibited higher cytotoxicity to human breast cancer cells and human cervical cancer cells when compared to the nanofiber structures of the similar Fmoc‐derivative. Overall this study provides a new understanding of the supramolecular self‐assembly of small‐molecular‐weight hydrogelators.     

Solvent‐Induced Helical Assembly and Reversible Chiroptical Switching of Chiral Cyclic‐Dipeptide‐Functionalized Naphthalenediimides

Understanding the roles of various parameters in orchestrating the preferential chiral molecular organization in supramolecular self‐assembly processes is of great significance in designing novel molecular functional systems. Cyclic dipeptide (CDP) chiral auxiliary‐functionalized naphthalenediimides (NCDPs 1 – 6 ) have been prepared and their chiral self‐assembly properties have been investigated. Detailed photophysical and circular dichroism (CD) studies have unveiled the crucial role of the solvent in the chiral aggregation of these NCDPs. NCDPs 1 – 3 form supramolecular helical assemblies and exhibit remarkable chiroptical switching behaviour (M‐ to P‐type) depending on the solvent composition of HFIP and DMSO. The strong influence of solvent composition on the supramolecular chirality of NCDPs has been further corroborated by concentration and solid‐state thin‐film CD studies. The chiroptical switching between supramolecular aggregates of opposite helicity (M and P) has been found to be reversible, and can be achieved through cycles of solvent removal and redissolution in solvent mixtures of specific composition. The control molecular systems (NCDPs 4 – 6 ), with an achiral or D ‐isomer second amino acid in the CDP auxiliary, did not show chiral aggregation properties. The substantial roles of hydrogen bonding and π–π interactions in the assembly of the NCDPs have been validated through nuclear magnetic resonance (NMR), photophysical, and computational studies. Quantum chemical calculations at the ab initio, semiempirical, and density functional theory levels have been performed on model systems to understand the stabilities of the right (P‐) and left (M‐) handed helical supramolecular assemblies and the nature of the intermolecular interactions. This study emphasizes the role of CDP chiral auxiliaries on the solvent‐induced helical assembly and reversible chiroptical switching of naphthalenediimides.     

Melamine driven supramolecular self‐assembly of nucleobase derivatives in water

Water‐soluble supramolecular polymers, especially made up of biomolecules, are ideally suited to build new biomaterials that can mimic or interact with dynamic, biological environments. Here, two derivatives from thymine (T), that is N‐[2‐(3,4‐Dihydro‐5‐methyl‐2,4‐dioxo‐1(2H)‐pyrimidinyl)acetyl]‐L‐phenylalanine (T‐phe) and N‐(2‐Aminoethyl)‐3,4‐dihydro‐5‐methyl‐2,4‐dioxo‐1(2H)‐pyrimidineacetamide (T‐NH₂) were synthesized. Then the optimal condition for self‐assembly of T‐phe and T‐NH₂ driven by melamine (M) was explored. It was observed that M/T kept at 1:3 with equivalent T‐phe and T‐NH₂ under neutral environment resulted in long fibers (>1 μm) with extremely high aspect ratios, which suggested that electrostatic and π‐stacking interactions could be effectively orchestrated by hydrogen bonds to direct the hierarchical assembly. Furthermore, hydrogels were spontaneously generated with a concentrated solution of T‐phe, T‐NH₂, and M due to the fibril entanglement. Given its biomimetic nature and efficient self‐assembly process, this newly developed supramolecular polymer stacked by tetrameric structures represented an innovative concept and pathway for novel bio‐inspired materials. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 789–796     

Substrate-induced adjustment of “slipped” π–π stacking: en route to obtain 1D sandwich chain and higher order self-assembly supramolecular structures in solid state

‘Slipped’ π?π stacking between flexible macrocycle 1⁴⁺ (cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylene benzene)) and neutral small molecules induce one-dimensional (1D) ‘sandwich’ chain self-assembly. Unlike most of the reported π?π stacking system, the 1D “sandwich” chain expands with the direction parallel to stacking π surfaces on 1⁴⁺ and that on molecule 2, 3, 4 or 5 (2 = p-xylene, 3 = benzene-1,4-diamine, 4 = 4,4′-bipyridine, 5 = [1,1′-biphenyl]-4,4′-diol). Moreover, the π?π stacking modes of 1D self-assembly are seriously small molecule adduct dependent. Combined with the other weak interactions (e.g. intermolecular hydrogen bonding), the new substrate design and control strategy can expand the 1D ‘sandwich’ chain (e.g. [1⁴⁺·4]_n) into higher order structure (e.g. two-dimensional (2D) network [1⁴⁺·4·6]_n, 6 = hydroquinone) even in large scale (~280 mg). This 2D network structure, which keeps stable under 423 K, shows highly selective gas absorption of CO₂ over N₂.     

Influence of hydrogen bonds between sidechains and cooperativity on self‐assembly of the cyclopeptides

The self‐assembly of four cyclic D,L‐octapeptides, [‐(D‐Ala‐Gln)₄‐], [‐(D‐Val‐Gln)₄‐], [‐(D‐Leu‐Gln)₄‐], and [‐(D‐Phe‐Gln)₄‐], was investigated on the theory level in detail. Based on these cyclic peptides, which contain L‐Gln residues and possess C₄ symmetry, a series of oligomers were constructed according to different stacking modes as well as interaction patterns. We employed the semiempirical molecular orbital method AM1 to optimize the structures of all the oligomers, some of which were further studied using density functional method B3PW91/6‐31G to calculate the interaction energies. The studies indicate that when these cyclopeptides aggregate to form oligomers, or even nanotubes, four more hydrogen bonds could form between the sidechains of L‐Gln residues in addition to eight hydrogen bonds formed between the backbones of adjacent two cyclic peptides, a result that would clearly affect the self‐assembling process of cyclic peptides. The main effects can be summarized as follows. First, the dimers of these cyclic peptides with C₄ symmetry are more stable than those with D₄ symmetry due to their additional H‐bonds between Gln sidechains. Second, for the self‐assembly of the cyclopeptides, there is a competition between parallel and antiparallel stacking modes in lower oligomers such as dimers. However, with an increasing degree of oligomerization, energetically there is an increased possibility for the cyclic peptides to take the parallel stacking mode in assembly. Finally, the synergetic effect of weak interactions is the fundamental driving force for cyclic peptides to form stable nanotubes. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Incorporation of Hexa‐peri‐hexabenzocoronene (HBC) into Carbazole–Benzo‐2,1,3‐thiadiazole Copolymers to Improve Hole Mobility and Photovoltaic Performance

Hexa‐peri‐hexabenzocoronene (HBC) is a discotic‐shaped conjugated molecule with strong π–π stacking property, high intrinsic charge mobility, and good self‐assembly properties. For a long time, however, organic photovoltaic (OPV) solar cells based on HBC demonstrated low power conversion efficiencies (PCEs). In this study, two conjugated terpolymers, poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5′‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] (PCDTBT)‐ 5 HBC and PCDTBT‐ 10 HBC, were synthesized by incorporating different amounts of HBC as the third component into poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5′‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] (PCDTBT) through Suzuki coupling polymerization. For comparison, the donor–acceptor (D –A) conjugated dipolymer PCDTBT was also synthesized to investigate the effect of HBC units on conjugated polymers. The HBC‐containing polymers exhibited higher thermal stabilities, broader absorption spectra, and lower highest‐occupied molecular orbital (HOMO) energy levels. In particular, the field‐effect mobilities were enhanced by more than one order of magnitude after the incorporation of HBC into the conjugated polymer backbone on account of increased interchain π–π stacking interactions. The bulk heterojunction (BHJ) polymer solar cells (PSCs) fabricated with the polymers as donor and PC₇₁BM as acceptor demonstrated gradual improvement of open‐circuit voltage (V_OC) and short‐circuit current (J_SC) with the increase in HBC content. As a result, the PCEs were improved from 3.21 % for PCDTBT to 3.78 % for PCDTBT‐ 5 HBC and then to 4.20 % for PCDTBT‐ 10 HBC.