The photodissociation dynamics of naphthalene cluster ions, (C10H8)(n)(+) with n = 2-7, in the visible and near-IR wavelength regions have been probed by photoionization-photofragmentation time-of-flight mass spectroscopy. An intracluster reaction leading to production of a C11H9+ ion is observed when the parent cluster ions are excited with near-IR photons, while only intramolecular fragmentation pathways occur following visible band excitation. The formation of C11H9+, which is assumed to possess the benzotropylium structure, is ascribed to a photochemical rearrangement of the dimer ion core produced in the parent clusters upon multiphoton excitation via the intervalence transition band. The intracluster reaction is observed only for parent cluster sizes n greater than or equal to 4, which suggests that the dimer ion core must be surrounded by a solvent cage involving at least two neutral molecules. We propose that the existence of a dimer core structure plays an important role in the photochemistry that occurs subsequent to excitation into the intervalence transition band.