Regiospecific and nonlinear substituent effects on the electronic and fluorescence spectra of phthalocyanines (Pcs) are reported. Alkoxyl groups at beta positions shift the Q band slightly, but those at alpha positions give a significant shift to the red. Concerning the splitting of the Q(0-0) band of metal-free Pcs and the quantum yield of fluorescence emission, alkoxyl groups at beta positions increase the values while those at a positions decrease them.