Two p-type conjugated polymers with disparate optical and electronic properties, PB3T and PB2T, were developed and applied in fullerene-free polymer solar cells (PSCs). The photovoltaic performance of the PB3T-based PSC device processed by anisole achieved a high power conversion efficiency of 11.9% with a Jsc of 18.8 mA cm−2 and Voc of 1.00 V.