The changes in electronic structure of the tetracyanoplatinate complex accompanying the transition [Pt(CN)2−4]n(insulator) + oxidant → [Pt(CN)2 −q+4]n(conductor) have been investigated with a cluster model approach. Calculations for trimer (n = 3) cluster models of the insulator and conductor have been performed with the self-consistent-field Xα Dirac scattered-wave method. Based on the cluster electronic structure, we infer that the valence band edge in the insulator is not dzz like, but consists of metal (dδ + dπ) and ligand character. Partial oxidation of this band results in a shortening of the inter-stack distance, leading in turn to a partially occupied dzz-like valence band. Thus electron transport occurs along the Pt backbone.