Oxidation, imidation, and S-methylation reactions of five-and six-membered 1, 3- thiasilacycloalkanes have been examined under various conditions. The S-functional derivatives of 1, 3-thiasilacycloalkanes undergo solvolytic Si C (S) bond cleavage in protic media. The ease of the ring opening depends on the S-functionality and on the ring size.