A series of three new 1-(2,6-diisopropylphenyl)-2,5di(2-thienyl)pyrrole-based polymers such as poly[1-(2,6-diisopropylphenyl)-2,5-di(2-thienyl)pyrrole] (PTPT), poly[1,4-(2,5bis(octyloxy)phenylene)-alt-5,5'-(1-(2,6-diisopropylphenyl) -2,5-di(2thienyl) pyrrole)] (PPTPT), and poly[2,5-(3-octylthiophene)-alt-5,5'(1-(2,6-diisopropylphenyl)-2,5-di(2-thienyl) pyrrole)] (PTTPT) were synthesized and characterized. The new polymers were readily soluble in common organic solvents and the thermogravimetric analysis showed that the three polymers are thermally stable with the 5% degradation temperature > 379 degrees C. The absorption maxima of the polymers were 478, 483, and 485 nm in thin film and the optical band gaps calculated from the onset wavelength of the optical absorption were 2.15, 2.20, and 2.13 eV, respectively. Each of the polymers was investigated as an electron donor blending with PC70BM as an electron acceptor in bulk heterojunction (BHJ) solar cells. BHJ solar cells were fabricated in ITO/PEDOT:PSS/polymer:PC70BM/TiOx/Al configurations. The BHJ solar cell with PPTPT:PC70BM (1:5 wt %) showed the power conversion efficiency (PCE) of 1.35% (J(sc) = 7.41 mA/cm(2), V-oc = 0.56 V, FF = 33%), measured using AM 1.5G solar simulator at 100 mW/cm(2) light illumination. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5514-5521, 2010