Abstract: Modified rhodamine 6G molecule (Rh Al) with polymerizable double bonds has been copolymerized with methyl methacrylate (MMA) and 1,8 naphthalimide derivative (N AE). The percents of the two monomers (Rh Al and N AE) and the average molecular weight of the copolymers have been measured. Their absorption spectra show that there is little or no interaction between the two chromophores in their ground state. However, their fluorescence spectra indicate that the fluorescence emission of N AE is partly quenched and that of Rh Al is improved in some copolymers, which shows that in the excited state there exists very effective intramolecular singlet singlet energy transfer (Intra SSET) from N AE to Rh Al in these copolymers.