The functional diamines 3,3'-diaminochalcone and bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide were successfully prepared by simple and convenient procedures with short reaction times, and the overall yields were 78 and 70%, respectively. Copolyimides prepared from 3,3'-diaminochalcone, bis(3-aminophenyl)3,5-bis(trifluoromethyl)phenyl phosphine oxide, and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride exhibited excellent solubility in several organic solvents, such as dimethyl sulfoxide, N,N-dimethylformamide, N-methyl pyrrolidone, tetrahydrofuran, and acetone. They also showed very good thermal stability even up to 450 degrees C for 5% weight loss (by thermogravimetric analysis) in nitrogen and a high glass-transition temperature up to 274 degrees C (by differential scanning calorimetry) in nitrogen. The copolymers' adhesive and photoreactive properties were also investigated, and it was confirmed that the copolyimide containing chalcone and phosphine oxide moieties in the main chain had good adhesiveness and photoreactivity. (C) 2007 Wiley Periodicals, Inc.