Abstract
The synthesized perylenes 3,4,9,10-tetracarboxylic acid N,N′-ethyl, phenyl, ρ-anisyl, α-naphthyl and acetyl diimides have shown great variations in absorption and emission spectra. The variation in molar extinction coefficients and fluorescence quantum yields have indicated that steric and electronic effects, caused by N-substitution, alters emission characteristics of perylene diimides significantly.