New hetero-substituted charge-compensated cobalt bis(1,2-dicarbollide) derivatives were synthesized by the reaction of 8,8'-mu-iodo-3-commo-3-cobalta-bis(1,2-dicarba-closo-dodecaborane) [8,8'-mu-I-3,3'-Co(1,2-C2B9H10)(2)] with 1,4-thioxane, pyridine N-oxide, and tetrahydropyran. X-ray diffraction studies showed that the 8'-iodo-8-(pyridiniumoxy)eucosahydro-1,1',2,2'-tetracarba-3-commo-cobalta-closo-tricosaborate molecule has the gauche-conformation (the substituents are turned with respect to each other by 69.2A degrees). The positive charge is predominantly localized on the N(Py) atom.