The reaction of benzenesulfenic acid, generated in situ by thermal decomposition of 3‐(phenylsulfinyl)propanenitrile, with monosubstitutedacetylenes was experimentally and theoretically investigated at the DFT level using the MPW1B95 density functional. A computational model based on the Hard Soft Acid Base (HSAB) principle was evaluated for its ability to qualitatively and quantitatively predict