The reactions of 5-substituted dibenzothiophenium salts, having one or two substituents, with sodium alkoxides and benzenethiolate have been studied in the protic solvents. The results in Table I showed that the 5-substituted dibenzothiophenium salts with alkoxide ions mostly proceed via aromatic bimolecular nucleophilic substitution and ligand exchange as shown in Chart 7. It has been also found that the reactions of 5-substituted dibenzothiophenium salts with benzenethiolate ion support the validity of the mechanism proceed by the aromatic bimolecular nucleophilic substitution as shown in Table II.