The copolymerization of styrene or methyl methacrylate with 1,8-naphthalimide dyes to yield fluorescent side-group copolymers was investigated. During copolymerization, no changes occurred in the chromophoric systems of the dyes. Colorimetrically, it was found that more that 0.90% of the dyes were chemically bonded to the polymer chain. The effect of polymer coloration was proven by appropriate coloristic characterization.