Abstract: Using FeCl3 as catalyst, crosslinkable poly(3-(2-(methacryloyloxy)ethyl)thiophe) (P3MET) was synthesized by oxidative coupling polymerization. The structure, thermal stability and photovoltaic properties of the polymer were characterized by FT-IR, GPC, TGA, UV-Vis absorption and cyclic voltammetry measurements. Results indicate that the polymer with absorption onsets ranging from 350 nm to 573 nm in chloroform solution has an absorption peak at 410 nm and an optical bandgap of about 2.1 eV. The thermal decomposition temperature (Td) in the range of 300-400 °C demonstrates a good thermal stability. The electron affinities (LUMO level) and the ionization potential (HOMO level) of P3MET are 3.52 eV and 5.62 eV, respectively.