Non‐Conjugated Polymer Dots with Crosslink‐Enhanced Emission in the Absence of Fluorophore Units

A new type of fluorescent material is presented, which is called non‐conjugated polymer dots (NCPDs). The NCPDs only possess sub‐fluorophores (which are groups such as C?O, C?N, N?O) instead of typical conjugated fluorophore groups, and thus these materials should not have strong photoluminescence (PL) in the usual sense. Nevertheless, the PL of these sub‐fluorophores can be enhanced by chemical crosslinking or physical immobilization of polymer chains, which is named the crosslink‐enhanced emission (CEE) effect. The significant advances achieved by us and other groups on both experimental and theoretical aspects are discussed, and the covalent‐bond CEE, rigidity‐aggregated CEE, or supramolecular CEE in NCPDs is elaborated. Moreover, synthetic strategies, unique optical properties, and the promise of NCPDs in bio‐related fields, such as bioimaging and drug delivery, are systematically discussed.