Intramolecular proton transfer occurring in the ground and excited states of a series of structurally related aromatic molecules displaying strong internal hydrogen bonding is investigated. Applied spectroscopic techniques include electronic absorption and spectrofluorimetry, which are coupled to semiempirical ground-state (AM1) and excited-state (INDO/S-CI) MO calculations. The results allow one to discern the presence of excited state intramolecular proton transfer (ESIPT) and primary fluorescence phenomena in the studied compounds.