The interaction of [Os3W(mu-H)(mu-CO)(CO)(13)](-) anion with phenylacetylene in CHCl3 gave [Os3W(mu-H)(CO)(12){mu(3)-eta(3)-C(H)C(Ph)C(OH)}] in moderate yield. The compound has been fully characterized by both spectroscopic and crystallographic methods. Coupling of a phenylacetylene and a carbonyl ligand to form a cluster bound {mu(3)-eta(3)-C(H)C(Ph)C(OH)} moiety is observed.