Molybdenum monooxo compounds MoO(OAr)(4-n)Cl-n (n = 0-2, Ar = 2,6-Me2C6H3 or 2,6-i4-Pr2C6H3) have been synthesized starting from the dioxo precursor MoO2O2. The complexes are characterized spectroscopically and by X-ray diffraction. The formation mechanism likely involves phenol precoordination followed by addition across the Mo=O bond.