A high‐yielding alternative synthesis of the dppm‐bridged heteronuclear cluster RuOs3(μ‐H)2(CO)9(μ‐CO)2(μ‐dppm) (1) [dppm = bis(diphenylphosphanyl)methane] has been developed. Thermolysis of 1 resulted in dephenylation of both phosphane groups to afford the butterfly cluster RuOs3(CO)12(μ4,κ2:κ2‐PhPCH2PPh) (2). The reaction of 1 with selected alkynes afforded the products RuOs3(μ‐H)(CO)8(μ‐CO)(μ3,κ2:κ1‐PhPCH2PPh2)(μ3,η1:η2:η1‐L) (3) (L = alkyne) in which the alkyne is aligned parallel to an Os–Os bond(// Os‐Os isomer). The clusters incorporating internal alkynes underwent isomerization to the //Ru‐Os isomer by alkyne and hydride migration. Several other cluster products of these reactions were also identified, including RuOs3(μ‐H)(CO)8(μ‐CO)(μ3,κ2:κ1‐PhPCH2PPh2)(μ3,η1:η2:η1‐tBuC2CHO)(6) in which the methyl group of the alkyne has been oxidized to an aldehyde. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)