We report the observation of photorefractive (PR) effect in a solution processable, thiophene copolymer with a side chain nonlinear optical (NLO) chromophore, poly(3- octylthiophene-co-N-(3-thenyl)-4-amino-2-nitrophenol) [POMDT]. The copolymer exhibits moderately fast photoconductivity. When doped with second order NLO active azo dye, this copolymer exhibited large second order NLO activity, and low asymmetric two beam coupling (TBC) gain. Enhanced TBC gain was observed, when this composite material was plasticized. The observed photorefractive response time is of the order of seconds. The slower response is attributed to the presence of large volume fraction of the plasticizer in the composition, which reduces the charge carrier mobility. The results from photoconductivity, second harmonic generation and two beam coupling experiments are discussed.