Photocrosslinkable polyimide and polymethacrylate comprising chalcone moieties in the side chain were synthesized for fabricating the alignment layer of liquid crystals. Chalcone group was introduced into the side chain unit of the polymer backbone. We observed a photodimerization behavior either in solution or in film by irradiation of a UV light. Linearly polarized UV irradiation on the chalcone-polymer films induced optical anisotropy of the polymer film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.