We have synthesized and characterized two new carbazole-based conjugated polymers, PCDCN and PCDTA, incorporating two strong light-absorbing organic dyes. These polymers exhibit relatively low band gaps (similar to 1.5 eV) and broad absorption ranges (from 300 to 700 nm). We fabricated polymer solar cells incorporating these polymers as donors and [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as the acceptor. At a blending ratio of 1: 4, we obtained power conversion efficiencies, under simulated AM 1.5 (100 mW/cm(2)) conditions, of 2.31% and 2.47% for the PCDCN- and PCDTA-based devices, respectively. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5126- 5134, 2010