The reactions of some organobimetallic chlorides [CpMo(CO)(3)](2)BiCl, [CpM(CO)(3)](2)SnCl2, [CpMo(CO)(3)](2)InCl (Cp = eta(5)-C5H5; M = Mo, W) with sodium 3,6-di-tert-butyl-ortho-benzosemiquinolate in toluene were studied using the EPR spectroscopy. The possibility of formation of organoheterometallic complexes containing o-semiquinone ligand was shown.