In this article, a dye with naphthalimide and coumarin was configured and was fully characterized. Its emission behavior was investigated in medium polar solvent. The emission behavior shows that there is no obvious energy transfer between naphthalimide and coumarin. Therefore, both the emission of naphthalimide and coumarin exhibit in the emission spectra, including blue and yellow part. The emission in film and solid shows different character. In film, single emission peak was observed. However, the solid emission covered a broad scope, including blue and yellow integrant. All the emission color was indicated by (Commission Internationale de L'Eclairage) CIE coordinates. The CIE coordinate of solid emission (0.29, 0.33) is approaching the ideal white light.