Reactions between cis-dichlorobis(tetrahydrothiophene)platinum(II) with 2,2'-dilithio-4,4'bis(trifluoromethyl)biphenyl or 2,2'-dilithio-4,4'-difluorobiphenyl resulted in the unexpected formation of the sixfold coordinated platinum(IV)-complexes cis-bis(tetrahydrothiophene)bis[eta-2-4,4'-bis(trifluoromethyl)biphen-2,2'-diyl]platinum(IV) or cis-bis(tetrahydrothiophene)bis(eta-2-4,4'-difluorobiphen-2,2'-diyl)platinum(IV).