9,10-Phenanthrenequinone (phq) reacts with WCl 4(DME) and MoCl 4(OEt 2) 2 to give the complexes tetrachloro[9,10-phenanthrenediolato(2—)-O,O′]tungsten(VI) and tetrachloro[9,10-phenanthrenesemiquinonato(1—)-O,O′]molybdenum(V), respectively; and with the oxohalide complexes MOCl 3(DME) (M = Mo, W) to give the complexes trichlorooxo[9,10-phenanthrenequinone-O,O′]molybdenum(V) and trichlorooxo[9,10-phenanthrenesemiquinonato(1—)-O,O′]tungsten(VI). Tetrachloro[3,4,5,6-tetrachloro-1,2-benzenediolato(2—)-O,O′]molybdenum(VI) is obtained in less than 50% yield by reaction of tetrachloro-1,2-benzoquinone (tcq) with MoCl 5, and tetrachloro[3,4,5,6-tetrachloro-1,2-benzenediolato(2—)-O,O′]tungsten(VI) is obtained in quantitative yield by reaction of WCl 6 with tcq, concomitant with oxidation of the toluene solvent. Tetrachloro[9,10-phenanthrenesemiquinonato(1—)-O,O′]molybdenum(V) reacts with t-BuOSiMe 3 to give dichlorooxo[1,1-oxybis(ethane)][9,10-phenanthrenediolato(2—)-O,O′] molybdenum(VI). Based on analytical, IR and magnetic data suggested assignments of formal oxidation states of the metal and the quinone ligands in the complexes are presented.