A selenophene analogue (P3HS) of poly(3-hexylthiophene), P3HT, has been investigated as a replacement for P3HT in bulk heterojunction solar cells. Polymer:PCBM films and devices of both materials are directly compared by studying morphology, optical properties, and device performance. Preliminary optimisation of P3HS:PCBM devices gave promising results with a power conversion energy slightly lower than that of an optimised P3HT:PCBM device measured under identical conditions.