EHMO calcns. were carried out for the homologous series [CuCo(CO4)]n with n either finite or infinite. Bi-center bonding is essentially existed between Cu-Co couple but almost neglected with respect to a Cu-Cu pair. The monomer species is active because of a low lying empty frontier orbitals with large populations around Cu (or Au) atom which favors combination with a donor or self-polymd. The relation between the infinite chain and oligomers is well indicated by the likeness of band and approx. band derived from energy spectrum of the tetramer. This perhaps provides a possibility to predict and rationalize the polymer behaviors in terms of those known events of the oligomers.

Key words: CARBONYL COMPLEX, COPPER COMPLEX, BAND STRUCTURES, COBALT COMPLEX, BAND THEORY, HUCKEL MOLECULAR ORBITAL