Cyanide-bridged mixed-valence Co-Fe multi-nuclear complexes, 0D molecular Prussian blue analogues (PBAs), have variable molecular structures and flexible electronic states. In this highlight review, the redox chemistry of the 0D Co-Fe molecular PBAs will be of focused to explain their electronic states and bistability induced by intramolecular electron transfer. In addition, dimensionally controlled assembly of molecular PBAs will be introduced.