The dehydrogenation of cyclohexane and hydrogenation of benzene and toluene were studied on alumina- and NaY-supported Pt, Co and Pt-Co catalysts. The toluene/benzene adsorption equilibrium constant ratios were also determined. Hydro-dehydrogenation data were compared with the activities of these catalysts in CO conversion and methane H-1-H-2 exchange data determined and published earlier for the same catalysts. Addition of Co to Pt reduced the hydro-dehydrogenation conversion rates. This effect was substantially stronger for benzene and toluene hydrogenation than that for dehydrogenation of cyclohexane. The turnover frequency (TOF) value for cyclohexane dehydrogenation indicated a synergy effect between Pt and Co in case of alumina supported Pt:Co sample of 50:50 at%. The TOF values indicated also the existence of significant "cooperation" between Pt and Co in PtCo/Al2O3 Catalysts. Synergy, found for all samples in formation of oxygenates from CO is elucidated on the basis of Pt-Co interaction, indicated by the increased toluene/benzene adsorption equilibrium constant ratio on alumina supported PtCo catalysts. A positive correlation was observed between adsorption equilibrium constants and conversion rates of the different hydrocarbons.