Reaction of Cp2∗Mo 2 O 5 with HSCH 2 CH 2 COOH in acidic (by CF 3 COOH) 50:50 MeOH–H 2 O solvent at room temperature yields compound Cp2∗Mo 2 (μ-O)(μ-SCH 2 CH 2 CO 2 ) 2 , a dinuclear diamagnetic Mo IV compound with a two-leg-sharing bis(four-legged piano stool) structure and a Mo–Mo distance of 2.6833(6)Å. A reaction monitoring by ESI MS shows the formation of an intermediate 18 mass units heavier, interpreted as a dihydroxo analogue. Electrochemistry shows a reversible, pH independent oxidation process and an irreversible, pH-dependent reduction process. Contrary to a recently published analogous reaction with the closely related HSCH 2 COOH substrate, this process does not lead to C–S bond cleavage.