The catalytic activities of reduced (relative to Mo[superscript]4+) molybdenum sulfides, known as Chevrel phases, have been evaluated for thiophene and benzothiophene hydrodesulfurization (HDS) and 1-butene hydrogenation (HYD). These materials have been found to have HDS activities comparable to, or greater than, model unpromoted and cobalt-promoted MoS[subscript]2 catalysts; in contrast, Chevrel phases exhibit low activities for 1-butene HYD;X-ray powder diffraction and laser Raman spectroscopy analysis of the used (10 hours of thiophene reaction) catalysts indicated that the bulk structures were stable under reaction conditions. XPS analysis demonstrated that reduced molybdenum oxidation states were present at the surface, compared to the Mo[superscript]4+ state of MoS[subscript]2 catalysts;The effect of the oxidation state of molybdenum on the catalytic HDS of thiophene was investigated using a series of lead-lutetium Chevrel phases with compositions of Lu[subscript]1.2xPbMo[subscript]6S[subscript]8 for 0≤ x≤ 0.2, and Lu[subscript]1.2xPb[subscript]1-xMo[subscript]6S[subscript]8 for 0.2