Reaction of the organorhenium(V) complex (η 5-C 5Me 5)ReOCl 2 ( 1) with the pentasulfidotitanium compound (η 5-C 5H 5) 2TiS 5 ( 2) in carbon disulfide or methyl-ene chloride solution at room temperature yields the novel compound oxo(η 5-penta- methylcyclopentadienyl)(η 2 tetrasulfido)rhenium(V) ( 3) as black, air-stable crystals. An X-ray structural study revealed the presence of two crystallographic independent molecules with nonplanar cyclic ReS4 units and rhenium-sulphur distances of 226.4( 1) and 224.4( 2) pm, respectively. The overall geometry around rhenium is best described as a distorted pyramid, with the π-bonded pentamethylcyclopentadienyl ligand in the apical position of this polyhedron. A similar geometry around the heavy-metal atom (X-ray crystallography) has been determined for the related organovanadium(V) complex (η 5-C 5H 5)VO(SC 6H 5) 2 ( 5a) which is obtained from the reaction of (η 5-C 5H 5)VOCl 2 ( 4) with the sodium salt of thiophenol.