Aromatic sulfoxides are photochemically active molecules. Much of that reactivity has been attributed to the previously uncharacterized triplet states of these molecules. At 77 K in ether/isopentane/ethanol (EPA) glass, aromatic sulfoxides are shown to have weak phosphorescence. The triplet energies are a few kilocalories per mole higher than the corresponding ketones; the diaryl sulfoxides are about 3 kcal/mol lower than the corresponding ketones, and the diaryl sulfoxides are about 3 kcal/mol lower than the corresponding aryl methyl sulfoxides. For instance the triplet energy of diphenylsulfoxide is 78 kcal/mol, whereas the triplet energy of methyl phenyl sulfoxide is estimated to be 81 kcal/mol. The lifetimes of emission are generally under 100 ms. From the diffuse vibrational structure of the spectra, the lifetimes, and the effect of solvent on the triplet energy, it is concluded that the triplets are delocalized aromatic states that involve substantial charge transfer off the oxygen atom.