Enhanced Performance of Benzothieno[3,2‐b]thiophene (BTT)‐Based Bottom‐Contact Thin‐Film Transistors

Three new benzothieno[3,2‐b]thiophene ( BTT ; 1 ) derivatives, which were end‐functionalized with phenyl ( BTT‐P ; 2 ), benzothiophenyl ( BTT‐BT ; 3 ), and benzothieno[3,2‐b]thiophenyl groups ( BBTT ; 4 ; dimer of 1 ), were synthesized and characterized in organic thin‐film transistors (OTFTs). A new and improved synthetic method for BTT s was developed, which enabled the efficient realization of new BTT ‐based semiconductors. The crystal structure of BBTT was determined by single‐crystal X‐ray diffraction. Within this family, BBTT , which had the largest conjugation of the BTT derivatives in this study, exhibited the highest p‐channel characteristic, with a carrier mobility as high as 0.22 cm² V^?1 s^?1 and a current on/off ratio of 1×10⁷, as well as good ambient stability for bottom‐contact/bottom‐gate OTFT devices. The device characteristics were correlated with the film morphologies and microstructures of the corresponding compounds.     

Monitoring photo‐induced transformations in crystals of 2,6‐difluorocinnamic acid under ambient conditions

Several conditions need to be fulfilled for a photochemical reaction to proceed in crystals. Some of these conditions, for example, geometrical conditions, depend on the particular type of photochemical reaction, but the rest are common for all reactions. The mutual directionality of two neighbouring molecules determines the kind of product obtained. The influence of temperature on the probability of a photochemical reaction occurring varies for different types of photochemical reaction and different compounds. High pressure imposed on crystals also has a big influence on the free space and the reaction cavity. The wavelength of the applied UV light is another factor which can initiate a reaction and sometimes determine the structure of a product. It is possible, to a certain degree, to control the packing of molecules in stacks by using fluoro substituents on benzene rings. The crystal and molecular structure of 2,6‐difluorocinnamic acid [systematic name: 3‐(2,6‐difluorophenyl)prop‐2‐enoic acid], C₉H₆F₂O₂, (I), was determined and analysed in terms of a photochemical [2 + 2] dimerization. The molecules are arranged in stacks along the a axis and the values of the intermolecular geometrical parameters indicate that they may undergo this photochemical reaction. The reaction was carried out in situ and the changes of the unit‐cell parameters during crystal irradiation by a UV beam were monitored. The values of the unit‐cell parameters change in a different manner, viz. cell length a after an initial increase starts to decrease, b after a decrease starts to increase, c increases and the unit‐cell volume V after a certain increase starts to decrease. The structure of a partially reacted crystal, i.e. containing both the reactant and the product, namely 2,6‐difluorocinnamic acid–3,4‐bis(2,6‐difluorophenyl)cyclobutane‐1,2‐dicarboxylic acid (0.858/0.071), 0.858C₉H₆F₂O₂·0.071C₁₈H₁₂F₄O₄, obtained in situ, is also presented. The powder of compound (I) was irradiated with UV light and afterwards crystallized [as 3,4‐bis(2,6‐difluorophenyl)cyclobutane‐1,2‐dicarboxylic acid toluene hemisolvate, C₁₈H₁₂F₄O₄·0.5C₇H₈] in a space group different from that of the crystal containing the in‐situ dimer.     

Convenient Synthesis of Spiro[benzo[d]pyrrolo[2,1‐b]thiazole‐3,2′‐indenes] Derivatives via Three‐Component Reaction

The three‐component reaction of N‐phenacylbenzothiazolium bromides, aromatic aldehydes and indane‐1,3‐dione in ethanol at room temperature in the presence of triethylamine as base afforded functionalized spiro[benzo[d]pyrrolo[2,1‐b]thiazole‐3,2′‐indenes] in good yields and with high diastereoselectivity. The ¹H NMR data and single crystal structure clearly indicated that the obtained spiro compounds predominately have one diastereoisomer.     

Nanomagnetically modified thioglycolic acid (γ‐Fe2O3@SiO2‐SCH2CO2H): Efficient and reusable green catalyst for the one‐pot domino synthesis of spiro[benzo[a]benzo[6,7]chromeno[2,3‐c]phenazine] and benzo[a]benzo[6,7]chromeno[2,3‐c]phenazines

Superparamagnetic nanoparticles of modified thioglycolic acid (γ‐Fe₂O₃@SiO₂‐SCH₂CO₂H) represent a new, efficient and green catalyst for the one‐pot synthesis of novel spiro[benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazine] derivatives via domino Knoevenagel–Michael–cyclization reaction of 2‐hydroxynaphthalene‐1,4‐dione, benzene‐1,2‐diamines, ninhydrin and isatin. This novel magnetic organocatalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least six times without significant loss in its activity. The catalyst was fully characterized using various techniques. This procedure was also applied successfully for the synthesis of benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazines.     

2‐Bromo‐1,3‐bis[2‐(2‐naphthyl)vinyl]benzene benzene hemisolvate and 9‐bromodinaphth[1,2‐a:2′,1′‐j]anthracene

2‐Bromo‐1,3‐bis[2‐(2‐naphthyl)vinyl]benzene benzene hemisolvate, C₃₀H₂₁Br·0.5C₆H₆, (I), with two formula units in the asymmetric unit, exists in the crystal structure in a conformation in which the trans (2‐naphthyl)vinyl substituents on the central bromobenzene moiety appear as nearly fully extended `wings', while 9‐bromodinaphth[1,2‐a:2′,1′‐j]anthracene, C<sub>30</sub>H<sub>17</sub>Br, (II), adopts a highly nonplanar `manta‐ray' shape, with the H atoms in the interior of the molecule within van der Waals contact distances. The packing of the significantly twisted molecules of (I) generates large voids which are filled by benzene solvent molecules, while molecules of (II) stack compactly with all C—Br bonds parallel within the stack.     

Synthesis of new 5‐substitutedbenzo[b]thiophene derivatives

Previous works of our group have dealt with the synthesis of 1‐(aryl)‐3‐[4‐(aryl)piperazin‐1‐yl]propane derivatives in the search for new and efficient antidepressants with a dual mode of action: serotonin reuptake inhibition and 5‐HT_1A receptor afinity [1‐4]. From these studies we concluded that the 3‐[4‐(aryl)piperazin‐1‐yl]‐1‐(benzo[b]thiophen‐3‐yl)propane derivatives led to the best results. The continuation of this research project required the preparation of some new 3‐acyl‐5‐substituted benzo[b]thiophenes with a wide variety of substituents at the 5 position, ranging from nitro to hydroxyl derivatives. To obtain these derivatives we acylated the corresponding 5‐substituted benzo[b]thiophenes when it was possible.     

3‐[5‐(4‐Chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid and the corresponding methyl ester

The synthesis of 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid, C₁₉H₁₇ClN₂O₃, (I), and its corresponding methyl ester, methyl 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionate, C₂₀H₁₉ClN₂O₃, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single‐crystal X‐ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z′ = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen‐bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C—H...A interactions, despite the lack of any functional groups for classical hydrogen bonding.     

Hexaaquanickel(II) bis[2‐carboxylato‐2‐(isothiouronium‐S‐ylmethyl)propane‐1,3‐diyl phosphate] hexahydrate

In the title complex, [Ni(H₂O)₆](C₆H₁₀N₂O₆PS)₂·6H₂O, the asymmetric unit consists of one‐half of an Ni atom (which lies on an inversion centre) with three coordinated water molecules, one complete 2‐carboxylato‐2‐(isothiouronium‐S‐ylmethyl)propane‐1,3‐diyl phosphate anion and three noncoordinated water molecules. The hexaaquanickel(II) cations have distorted octahedral coordination and are connected via water chains to form two‐dimensional supramolecular networks parallel to the ab plane. The phosphate ester anion is linked via N—H...O and O—H...O hydrogen bonds, thus creating various ring, dimer and chain hydrogen‐bonding patterns, and building up a second two‐dimensional supramolecular network parallel to the ab plane. The crystal structure is further stabilized by an intra‐ and interlayer hydrogen‐bond network. This work illustrates that a carboxylate with a caged phosphate ester can open its ring in the presence of dichloridotetrakis(thiourea)nickel, and the resulting polyfunctional anion can be used for constructing a complex hydrogen‐bonding scheme.     

Two similarly substituted benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐diones: supramolecular structures in two and three dimensions

The molecules of 8‐methyl‐7,10‐diphenyl‐5H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐dione, C₂₇H₁₇N₃O₂, (I), are weakly linked into chains by a single C—H...O hydrogen bond, and these chains are linked into sheets by a π–π stacking interaction involving pyridyl and aryl rings. In 8‐methyl‐7‐(4‐methylphenyl)‐10‐phenyl‐5H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐dione, C₂₈H₁₉N₃O₂, (II), the molecules are linked into a three‐dimensional framework structure by a combination of C—H...N, C—H...O and C—H...π(arene) hydrogen bonds, together with a π–π stacking interaction analogous to that in (I).     

Synthesis of 1‐Methyl‐3‐aryl‐substituted Titanocene and Zirconocene Dichlorides and Crystal Structure of Bis[η5‐1‐methyl‐3‐(α, α‐dimethylbenzyl) cyclopentadienyl] titanium Dichloride

The syntheses of a series of l‐methyl‐3‐aryl‐substituted titanocene and zirconocene dichlorides are reported. These complexes are synthesized by the reaction of 2‐ and 3‐methyl‐6, 6‐dimethylfulvenes (1:4) with aryllithium, followed by the reaction with TiCl₄·2THF, ZrCl₄ and (CpTiCl₂)₂O respectively, to give complexes 1–5. The complex [η⁵‐1‐methyl‐3‐(α, α‐dimethylbenzyl) cyclopentadienyl] titanium dichloride has been studied by X‐ray diffraction. The red crystal of this complex is monoclinic, space group P2_t/C with unit cell parameters: a =6.973(6) × 10^?1 nm, b =36.91(2) × 10^?1 nm, c = 10.063(4) × 10^?1 nm, α=β= γ = 93.35(5)°, V = 2584(5) × 10^?3 nm³ and Z = 4. Refinement for 1004 observed reflections gives the final R of 0.088. There are four independent molecules per unit cell.     

Crystal structures of functional building blocks derived from bis(benzo[b]thiophen‐2‐yl)methane

The syntheses of three bis(benzo[b]thiophen‐2‐yl)methane derivatives, namely bis(benzo[b]thiophen‐2‐yl)methanone, C₁₇H₁₀OS₂, (I), 1,1‐bis(benzo[b]thiophen‐2‐yl)‐3‐(trimethylsilyl)prop‐2‐yn‐1‐ol, C₂₂H₂₀OS₂Si, (II), and 1,1‐bis(benzo[b]thiophen‐2‐yl)prop‐2‐yn‐1‐ol, C₁₉H₁₂OS₂, (III), are described and their crystal structures discussed comparatively. The conformation of ketone (I) and the respective analogues are rather similar for most of the compounds compared. This is true for the interplanar angles, the C_aryl—C_bridge—C_aryl angles and the dihedral angles. The best resemblance is found for a bioisotere of (I), viz. 2,2′‐dinaphthyl ketone, (VII). By way of interest, the crystal packings also reveal similarities between (I) and (VII). In (I), the edge‐to‐face interactions seen between two napthyl residues in (VII) are substituted by S…π contacts between the benzo[b]thiophen‐2‐yl units in (I). In the structures of the bis(benzo[b]thiophen‐2‐yl)methanols, i.e. (II) and (III), the interplanar angles are also quite similar compared with analogues and related active pharmaceutical ingredients (APIs) containing the dithiophen‐2‐ylmethane scaffold, though the dihedral angles show a larger variability and produce unsymmetrical molecules.     

2‐[(E)‐(4‐Hydroxy‐3‐methoxybenzylidene)amino]‐N‐(2‐methylphenyl)‐4,5,6,7‐tetrahydro‐1‐benzothiophene‐3‐carboxamide

The title compound, C₂₄H₂₄N₂O₃S, exhibits antifungal and antibacterial properties. The compound crystallizes with two molecules in the asymmetric unit, with one molecule exhibiting `orientational disorder' in the crystal structure with respect to the cyclohexene ring. The o‐toluidine groups in both molecules are noncoplanar with the respective cyclohexene‐fused thiophene ring. In both molecules, there is an intramolecular N—H...N hydrogen bond forming a pseudo‐six‐membered ring which locks the molecular conformation and eliminates conformational flexibility. The crystal structure is stabilized by O—H...O hydrogen bonds; both molecules in the asymmetric unit form independent chains, each such chain consisting of alternating `ordered' and `disordered' molecules in the crystal lattice.     

Poly[[diaquabis(μ2‐1‐oxo‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐4‐carboxylato)copper(II)] dihydrate]

The asymmetric unit of the title complex, {[Cu(C₅H₆O₆P)₂(H₂O)₂]·2H₂O}_n, consists of half a Cu atom, one complete 1‐oxo‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐4‐carboxylate anion ligand and two non‐equivalent water molecules. The Cu atom lies on a crystallographic inversion centre and has an elongated axially distorted octahedral environment. A two‐dimensional layer structure parallel to (100) is formed as a result of the connectivity brought about by each anion bonding to two different Cu atoms via a carboxylate O atom and a bridging O atom of a C—O—P group. The water molecules participate in extensive O—H...O hydrogen bonding. Neighbouring layers are linked together by intermolecular hydrogen‐bonding interactions. The crystal structure is characterized by intra‐ and interlayer motifs of a hydrogen‐bonded network. This study demonstrates the usefulness of carboxylates with caged phosphate esters in crystal engineering.     

Synthesis,Characterization, Crystal and Molecular Structure of 1,5‐Dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine

The reaction of 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐one ( 3 ) with an alkylamine (butylamine, hexylamine or ethylenediamine) yields, quite unexpectedly and in the absence of catalyst, the novel compound 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine ( 4 ) as the sole, analytically pure, solid product, which was fully characterized. The structure of 4 was unequivocally solved by single‐crystal X‐ray‐diffraction analysis. The compound crystallizes in a monoclinic cell (space group P 2₁/c), with two molecules in the asymmetric unit, held together by intermolecular H‐bonds. Compound 4 could be interesting as a bi‐ or even tridentate ligand, and exhibits a strong fluorescence upon excitation at 310 nm. A mechanism, based on the observed C? N bond cleavage, is proposed.     

Crystal structure of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c][1,2,5]thiadiazole: distortion from a hypothetical higher‐symmetry structure

Nucleophilic substitution of F atoms in 5,6‐difluorobenzo[c ][1,2,5]thiadiazole (DFBT) for carbazole could be potentially interesting as a novel way of synthesizing building blocks for new conjugated materials for applications in organic chemistry. The crystal structures of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c ][1,2,5]thiadiazole (DCBT), C₃₀H₁₈N₄S, and its hydrate, C₃₀H₁₈N₄S·0.125H₂O, were investigated using single‐crystal X‐ray analysis. The hydrate contains two symmetry‐independent DCBT molecules. The dihedral angles between the plane of the central benzothiadiazole fragment and that of the carbazole units vary between 50.8 and 69.9°, indicating conformational flexibility of the DCBT molecule in the crystals, which is consistent with quantum chemical calculations. The analysis of the crystal packing of DCBT revealed that the experimental triclinic structure could be described as a distortion from a hypothetical higher‐symmetry monoclinic structure. The quantum chemical calculations of two possible monoclinic structures, which are related to the experimental structure by a shifting of molecular layers, showed that the proposed structures are higher in energy by 5.4 and 10.1 kcal mol⁻¹. This energy increase is caused by less dense crystal packings of the symmetric structures, which results in a decrease of the number of intermolecular interactions.     

α‐Tris(2,4‐pentanedionato‐κ2O,O′)chromium(III) at 290 and 110 K: a new δ phase at 110 K

The crystal structure of the title compound, [Cr(C₅H₇O₂)₃], has been determined at 290 and 110 K to provide information on thermal vibrations and disorder. The α polymorph at room temperature has been reported [Morosin (1965). Acta Cryst. 19 , 131–137]. The reinvestigation of this structure, presented here, indicates the presence of weak uninterpretable supercell reflections together with disorder streaks. The discussed structure can thus be considered as an average structure. After cooling to 110 K, a new δ polymorph was found, which is a superstructure of the α polymorph. The space group remains P2₁/c and the phase transition can therefore be considered as klassengleich. The unit‐cell volume increases by a factor of six, resulting in six independent molecules in the asymmetric unit.     

Synthesis and Crystal Structure of 4,7‐Diaryl‐5‐oxo‐4H‐benzo[b]pyran Derivatives

A green and convenient approach to the synthesis of a series of 4,7‐diaryl‐5‐oxo‐4H‐benzo[b]pyran derivatives from appropriate aromatic aldehydes and 5‐aryl‐1,3‐cyclohexanedione with malononitrile in the presence of dilute HCl as catalyst (30 mmol/L) is described. This method provides several advantages such as environmental friendliness, low cost, high yields, and simple work up procedure. The structures of all compounds were characterized by infrared (IR), mass spectrometry (MS), ¹H NMR, and elemental analysis. The crystal structure of trans/cis‐2‐amino‐3‐cyano‐7‐(4′‐methoxo‐phenyl)‐4‐phenyl‐5‐oxo‐4H‐benzo[b]pyran, g , was determined by single crystal X‐ray diffraction analysis. The crystal of compound g belongs to monoclinic with space group P 21/c, a = 8.477(3) nm, b = 18.948(6) nm, c = 24.915(7) nm, α = 90.00°, β = 107.388(11)°, γ= 90.00°, Z = 8, V = 3.819(2) nm³, R₁ = 0.0754, wR₂ = 0.2042.     

Synthesis and Structure–Property Relationships of 2,2′‐Bis(benzo[b]phosphole) and 2,2′‐Benzo[b]phosphole–Benzo[b]heterole Hybrid π Systems

The first comprehensive study of the synthesis and structure–property relationships of 2,2′‐bis(benzo[b]phosphole)s and 2,2′‐benzo[b]phosphole–benzo[b]heterole hybrid π systems is reported. 2‐Bromobenzo[b]phosphole P‐oxide underwent copper‐assisted homocoupling (Ullmann coupling) and palladium‐catalyzed cross‐coupling (Stille coupling) to give new classes of benzo[b]phosphole derivatives. The benzo[b]phosphole–benzo[b]thiophene and ‐indole derivatives were further converted to P,X‐bridged terphenylenes (X=S, N) by a palladium‐catalyzed oxidative cycloaddition reaction with 4‐octyne through the C_β? H activation. X‐ray analyses of three compounds showed that the benzo[b]phosphole‐benzo[b]heterole derivatives have coplanar π planes as a result of the effective conjugation through inter‐ring C? C bonds. The π–π* transition energies and redox potentials of the cis and trans isomers of bis(benzo[b]phosphole) P‐oxide are very close to each other, suggesting that their optical and electrochemical properties are little affected by the relative stereochemistry at the two phosphorus atoms. The optical properties of the benzo[b]phosphole–benzo[b]heterole hybrids are highly dependent on the benzo[b]heterole subunits. Steady‐state UV/Vis absorption/fluorescence spectroscopy, fluorescence lifetime measurements, and theoretical calculations of the non‐fused and acetylene‐fused benzo[b]phosphole–benzo[b]heterole π systems revealed that their emissive excited states consist of two different conformers in rapid equilibrium.     

Packing considerations of 10‐oxa‐9‐boraphenanthrene derivatives

The crystal structures of three products of the reaction of 2‐phenylphenol and BCl₃ have been determined. The structures show intriguing packing patterns and an interesting case of pseudosymmetry. In addition, one of the two polymorphs has a primitive monoclinic crystal system, but it is twinned and emulates an orthorhombic C‐centred structure. Tris(biphenyl‐2‐yl) borate, C₃₆H₂₇BO₃, ( III ), crystallizes with only one molecule in the asymmetric unit. The dihedral angles between the planes of the aromatic rings in the biphenyl moieties are 50.47 (13), 44.95 (13) and 42.60 (13)°. The boron centre is in a trigonal planar coordination with two of the biphenyl residues on one side of the BO₃ plane and the remaining biphenyl residue on the other side. One polymorph of 10‐oxa‐9‐boraphenanthren‐9‐ol, C₁₂H₉BO₂, ( V a ), crystallizes with two almost identical molecules (r.m.s. deviation of all non‐H atoms = 0.039 Å) in the asymmetric unit. All non‐H atoms lie in a common plane (r.m.s. deviation = 0.015 Å for both molecules in the asymmetric unit). The two molecules in the asymmetric unit are connected into dimers via O—H...O hydrogen bonds. A second polymorph of 10‐oxa‐9‐boraphenanthren‐9‐ol, ( V b ), crystallizes as a pseudo‐merohedral twin with two almost identical molecules (r.m.s. deviation of all non‐H atoms = 0.035 Å) in the asymmetric unit. All non‐H atoms lie in a common plane (r.m.s. deviation = 0.012 Å for molecule 1 and 0.014 Å for molecule A). Each of the two molecules in the asymmetric unit is connected into a centrosymmetric dimer via O—H...O hydrogen bonds. The main difference between the two polymorphic structures is that in ( V a ) the two molecules in the asymmetric unit are hydrogen bonded to each other, whereas in ( V b ), each molecule in the asymmetric unit forms a hydrogen‐bonded dimer with its centrosymmetric equivalent. 9‐[(Biphenyl‐2‐yl)oxy]‐10‐oxa‐9‐boraphenanthrene, C₂₄H₁₇BO₂, ( VI ), crystallizes with four molecules in the asymmetric unit. The main differences between them are the dihedral angles between the ring planes. Apart from the biphenyl moiety, all non‐H atoms lie in a common plane (r.m.s. deviations = 0.026, 0.0231, 0.019 and 0.033 Å for molecules 1, A, B and C, respectively). This structure shows pseudosymmetry; molecules 1 and A, as well as molecules B and C, are related by a pseudo‐translation of about in the direction of the b axis. Molecules 1 and B, as well as molecules A and C, are related by a pseudo‐inversion centre at ,,. Neither between molecules 1 and C nor between molecules A and B can pseudosymmetry be found.     

Dithienocyclopentathieno[3,2‐b]thiophene Hexacyclic Arene for Solution‐Processed Organic Field‐Effect Transistors and Photovoltaic Applications

We have developed a ladder‐type dithienocyclopentathieno[3,2‐b]thiophene ( DTCTT ) hexacyclic unit in which the central thieno[3,2‐b]thiophene ring was covalently fastened to two adjacent thiophene rings through carbon bridges, thereby forming two connected cyclopentadithiophene ( CPDT ) units in a hexacyclic coplanar structure. This stannylated Sn‐DTCTT building block was copolymerized with three electron‐deficient acceptors, dibromo‐thieno[3,4‐c]pyrrole‐4,6‐dione ( TPD ), dibromo‐benzothiadiazole ( BT ), and dibromo‐phenanthrenequinoxaline ( PQX ), by Stille polymerization, thereby furnishing a new class of alternating donor–acceptor copolymers: PDTCTTTPD , PDTCTTBT , and PDTCTTPQX , respectively. Field‐effect transistors based on PDTCTTPQX and PDTCTTBT yielded high hole mobilities of 0.017 and 0.053 cm² V^?1 s^?1, respectively, which are among the highest performances among amorphous donor–acceptor copolymers. A bulk heterojunction solar cell that incorporated PDTCTTTPD with the lower‐lying HOMO energy level delivered a higher V_oc value of 0.72 V and a power conversion efficiency (PCE) value of 2.59 %.