Palladium-catalyzed direct arylation polycondensation afforded a bithiazole-based homopolymer and donor–acceptor (D–A)-type copolymers where the bithiazole unit served as an acceptor unit. The results of polymerization strongly depended on the solubility of the polymers; long alkyl chain substituents were required for the formation of high-molecular-weight polymers in high yields owing to low solubility of the bithiazole-based polymers. X-ray diffraction studies revealed that the obtained polymers were highly crystalline. In particular, a well-ordered lamellar structure was observed in the D–A-type copolymer with flexible alkyl chains after thermal annealing, presumably owing to the combination of interchain interactions between the bithiazole units and the electrostatic D–A interactions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1396–1402

A naphthalenediimide (NDI)-based conjugated polymer was synthesized by a two-step direct C-H arylation sequence. In the first step, two ethylenedioxythiophene units were coupled to NDI by direct arylation. In the second step, the direct arylation polycondensation of the monomer, formed in the first step, with 2,7-dibromo-9,9-dioctylfluorene afforded the corresponding NDI-based conjugated polymer (PEDOTNDIF) with molecular weight of 21,500 in 91% yield. The optical and electrochemical properties of the polymer were evaluated. The polymer showed ambipolar behavior in organic field-effect transistors (OFETs). The electron mobility of PEDOTNDIF was estimated to be 2.3 × 10⁻⁶ cm² V⁻¹ s⁻¹ using an OFET device with source-drain (S-D) Au electrodes. A modified OFET device with S-D MgAg electrodes increased the electron mobility for PEDOTNDIF to 1.0 × 10⁻⁵ cm² V⁻¹ s⁻¹ due to the more suitable work function of these electrodes, which reduced the injection barrier to the semiconducting polymer. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1401–1407