The chemical reduction of [Co8Pt4C2(CO)24]2– (2–) with Na/naphthalene results, after workup, in the isolation of either [Co10Pt2C2(CO)22]4– (4–) or [Co8Pt4C2(CO)20]4– (4–), depending on the experimental conditions. All these species undergo several chemical and/or electrochemical redox reactions, disclosing the existence of structurally related dodecanuclear clusters n– (n = 0–4), n– (n = 2–6) and n–(n = 1–7). In the attempt to isolate more reduced species,n–, n– and n– undergo structural rearrangements resulting, among others, in the formation of the new species [Co10–xPt2+xC2(CO)24]2– (2–) (x = 0–2) structurally related to 2–. These dodecanuclear M12C2 dicarbido clusters are not isostructural and differ in the metal composition and/or the number of CO ligands. Nevertheless, they can be readily interconverted even if the interconversion reactions are not straightforward.