A variety of dibenzosuberenyl systems have been investigated by laser flash photolysis. Excitation of the parent alcohol, 5-dibenzosuberenol, in trifluoroethanol yields the corresponding carbocation via heterolysis of the C-OH bond. The carbocation shows a long-lived (> 100 {mu}s) absorption at 525 nm with a second band at 390 nm, is readily quenched by nucleophiles (k{sub q}(azide) = 1.1 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}), and fluoresces with a lifetime of 35 ns. In other solvents, the transient phenomena are dominated by the formation of the radical cation via a two-photon process. both dibenzosuberene and 5-phenyl-5-dibenzosuberenol also yield radical cations in a variety of polar solvents. The radical cations show absorption spectra with maxima at 470 nm and a broad band in the 700-nm region, have lifetimes in oxygenated solutions of >1.5 {mu}s, and react with a variety of nucleophiles. Their identity has been confirmed on the basis of their independent generation with the electron-transfer sensitizers chloranil and 1,4-dicyanonaphthalene and by reaction with 1,2,4-trimethoxybenzene.