The pentacyanopropenide that is unstable in ambient conditions is subsequently encapsulated in crystals of melamine . Melamine has been chosen as the host matrix due to its ability to effectively incorporate dopants. It is found that the colorful doped melamine crystals exhibit fluorescence at multiple wavelengths in the visible range. The fluorescence emission wavelength is observed to increase as the concentration of the TCNQ in the solution is raised. Based on the density-functional theory calculations, the concentrationdependent fluorescence is attributed to aggregates of pentacyanopropenide.