Effective inhibitor pairs have been obtained by targeted selection of the nature of ligands in Co(III) complexes and compounds containing nitrogen and sulfur donor atoms. Under the initiated ethylbenzene oxidation conditions (75A degrees C), the joint antioxidant activity of four Co(III) complexes, five amines, and a disulfide used in pairs has been studied. Plausible modes of oxidation chain termination by the newly formed Co(III) complexes [Co(dtcR(1)R(2))(3)-amine] and [(Co(ac,ac)(3)-amine] have been established. The specific features of the structure of the Co(III) complexes and amines responsible for the enhancement of the inhibiting activity in their application in pairs have been studied, a development that is important for designing other antioxidant systems.