Two chalcone-derivative isomers, 4,4＇-diaminochalcone (4DAC) and 3,3＇-diaminochalcone (3DAC), were synthesized and used as monomers together with tetracarboxylic dianhydrides to prepare novel photosensitive polyimides that contain a chalcone moiety in the main chain. The polyimides were characterized and their photochemical behavior was investigated as thin films and in solutions with the aid of ultraviolet and infrared spectroscopy. Compared with 4DAC-based polyimides, the 3DAC-based polyimides exhibited lower glass transition temperatures and higher photocrosslinking rates of the carbon-carbon double bond as well as higher photosensitivities obtained from the exposure characteristic curves, suggesting that an increase in the photoreactivity of the 3DAC-based polyimides might arise from the improved flexibility of their backbones. The polyimide from 3DAC and 6FDA (2,2-bis[3,4-dicarboxypheny]hexafluoropropane dianhydride) showed a photosensitivity of 33 mJ/cm(2) with a contrast of 1.5 upon light irradiation using a Xenon lamp.