Abstract-In this paper attention is given primarily to substitution reactions of photoexcited aromatic compounds with (non-excited) nucleophiles. At the end a brief discussion is presented on the less-well known, but no less interesting photoinduced electrophilic substitution reactions, followed by a schematic representation of the various possible ways of heterolytic reaction of an electronically excited aromatic molecule. Nucleophilic aromatic photosubstitution nowadays comprises a great number and variety of reactions. Without ignoring traditional photochemical characteristics (singlet vs triplet reaction, ir -irK or pj * excitation etc.) the authors offer a systematization based mainly on the nature and influence of substituents (electron attracting or donating) in the aromatic system and on kinetic features. For certain types of aromatic photosubstitution the results obtained by chemical and spectroscopic investigations permit speculation on their mechanism. The variety and subtlety of the photoinduced aromatic substitutions seem to be no less than that of their thermal counterparts notwithstanding the fact that these reactions generally proceed extremely fast (not far from encounter controlled). As in the field of concerted processes, in heterolytic aromatic substitutions the thermal and the photochemical reactions mutually complement each other in a theoretically intriguing and practically useful way
