A phenothiazine-diketopyrrolopyrrole polymer (PPT-DPP) with a thiophene spacer was synthesized with a number-average molecular weight of 17600. The new polymer exhibited an optical band-gap of 1.63 eV and a highest occupied molecular orbital energy level of 5.20 eV. Photovoltaic devices were fabricated using the polymer and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) with the configuration ITO/PEDOT:PSS/PPT-DPP:PC71BM/LiF/Al. The polymer-based devices exhibited power conversion efficiencies as high as 1.8%. Based on atomic force microscopy data, the device performance was related to the morphology of the active layers. (C) 2013 Elsevier B. V. All rights reserved.