We have examined the effect of copper oxidation state in the continuous gas phase coupled phenylacetylene hydrogenation (to styrene) with benzyl alcohol dehydrogenation (to benzaldehyde) over Cu/CeO₂. Analysis by H₂-TPR, XPS, XRD and STEM-EDX analyses demonstrates the generation of a range of Cu oxidation states (Cu⁰ (13-77%), Cu⁺ (13-74%), Cu2⁺ (0-55%)). The stepwise formation of styrene and ethylbenzene was promoted in the stand-alone phenylacetylene hydrogenation. An increase in Cu⁰/Cu+ (from H₂-TPR and XPS) enhanced H₂ chemisorption and styrene TOF, but with low hydrogen utilisation efficiency. The formation of benzaldehyde and toluene was promoted in the stand-alone dehydrogenation of benzyl alcohol, where benzaldehyde selectivity and TOF correlate with the concentration of Cu⁰. Full hydrogen utilisation, exclusive benzaldehyde/styrene formation and a (3-fold) greater styrene TOF (to attain 100% yield) was achieved in the coupled process, where hydrogenation/dehydrogenation activity correlates with Cu+/Cu⁰. This opens new directions for sustainable “hydrogen free” hydrogenations over non-noble Cu catalysts.