[Ar'SnCo]₂ (1, Ar' = C₆H₃-2,6{C₆H₃-2,6- ⁱPr₂}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(μ-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.