In this contribution, a dye (C-8-alkyl substituted Naphthalimide-Coumarin, CNC) with naphthalimide and coumarin incorporated together with -NHN = bridge unit. The compound was fully characterized by NMR and HRMS spectroscopic techniques. Highly emissive character was investigated in detail in various polar environments. The emission maximum varied from 430 to 470nm. In polycarbonate film, CNC is also highly emissive with 560nm emission peak. While in sold, the emission maximum was further shifted to 580nm due to the more tightly packing mode than that in film. The C-8-alkyl substitution enhances the solubility of CNC and also contributes most to its solid emission.