Two donor acceptor copolymers, PTVTBT and PTVTBO, using the highly pi-extended (E)-2-(2-(thiophen2-yl)vinyl)thiophen as an electron-rich unit and benzodiathiazole or benzoxadiazole as an electron-deficient one, were designed and synthesized via a Pd-catalyzed Stille-coupling method. The copolymers possess high thermal stability, broad absorption, low band gap, and good film-forming ability. Meanwhile the two polymers exhibit excellent hole transport properties when used as the active layer in polymer field-effect transistor devices. The highest hole mobility can reach to 0.25 and 0.50 cm(2) V-1 s(-1) for the PTVTBT and PTVTBO thin films, respectively. This work demonstrates that PTVTBT and PTVTBO would be promising semiconductors for developing cost-effective and large-scale production of flexible organic electronics. (C) 2015 Elsevier Ltd. All rights reserved.