The thiaplatinacycles, [PtL2(C,S-C12H8S)] and [PtL2(C,S-C13H1OS)] (L = PEt3, PMe3; L-2 = Ph2PCH2CH2PPh2), obtained from oxidative insertion of [(PtLn)-L-0] into dibenzothiophene and 4-methyldibenzothiophene are hydrodesulfurized by reaction with hydrogen (toluene, 20 atm, 100 degrees C) to biphenyl and 3-methylbiphenyl, respectively; addition of acidic alumina improves the reaction. These observations link the model systems and the latest generation of commercial second-stage HDS catalysts.