6-Amino-2-(3-chloro-2-hydroxy-propyl)benzo[de]isoquinoline-1,3-dione (DYE-A) and 2-benzyl-6hydroxy-benzo[de]isoquinoline-1,3-dione (DYE-B) have been successfully synthesized in our lab, and their structures have been proven by IR, NMR, and mass spectra. The fluorescence performance appears to be better for DYE-A than for DYE-B as a result of DYE-A having more electron donating substituents that are strongly excited when absorbing UV light. These fluorescent dyes have further reacted with toluene diisocyanate and other additives to form the fluorescent dye-based polyurethane (PU) ionomer molecules, and the structures of these molecules have been demonstrated by IR spectra. In aqueous solution, our experimental results indicate that the fluorescence performance is seen to be better for DYE-A than for DYE-B. Increased concentration of DYE-A molecule attached to the backbone of the PU ionomer molecule may reduce the fluorescence performance of this PU ionomer molecule, resulting from the intramolecular interaction between ionomer molecule itself. For the fluorescent dye-based PU ionomer molecule system, the average particle size of the fluorescent dye-based PU ionomer molecule in water increases with increasing concentration of the fluorescent dyes, as a result of increased free volume of the ionomer molecules. Our experimental results also illustrate that the tensile strength of self-cured film made by the fluorescent dye-based PU ionomer appears to increase with an increase in the concentration of DYE-A. This is the result of increased intermolecular interaction between ionomer molecules. (C) 2003 Wiley Periodicals, Inc.