The trinuclear oxo-acetylide metal cluster (eta(5)-C(5)Me(5))W(O)Re-2(CO)(8)(mu-CCPh) (1) reacts with thiophenol in refluxing toluene to afford the dinuclear metal complex (eta(5)-C(5)Me(5))W(O)Re(CO)(4)(mu-H)(mu-CCPh) (2) in 90% yield. Upon treatment with Me(3)NO in acetonitrile, complex 2 loses one CO ligand and is converted initially to an acetonitrile derivative, (eta(5)-C(5)Me(5))W(O)Re(CO)(3)(NCMe)(mu-H)(mu-CCPh) (4), and then to a head-to-tail dimer, [(eta(5)-C(5)Me(5))WRe(Co)(3)(mu-O)(mu-H)(mu-CCPh)](2) (5), through the formation of two W=O-Re bridges. Extended Huckel MO calculations indicate that the most likely site of electrophilic attack is the oxo oxygen atom, and in agreement with this prediction, protonation of 2 with CF3CO2H is suggested to give the unstable hydroxy complex 6.