[Ar'SnCo](2) (1, Ar' = C6H3-2,6{C6H3-2,6-Pr-i(2)}(2)), a rare metal-metal bonded cobalt-tin cluster with low-coordinate tin atoms, was prepared by the reaction of [K(thf)(0.2)][Co(1,5-cod)(2)] (cod = 1,5-cyclooctadiene) with [Ar'Sn(mu-Cl)](2). This reaction illustrates a promising synthetic strategy to access uncommon metal clusters. The structure of 1 features a rhomboidal Co2Sn2 core with strong metal-metal bonds between tin and cobalt and a weaker tin-tin interaction. Reaction of 1 with white phosphorus afforded [Ar'2Sn2Co2P4] (2), the first molecular cluster compound containing phosphorus, cobalt and tin.