Moreover, we studied the use of an organic substrate that yield value-added oxidation products as electron donors, thus avoiding the undesirably waste of energy by sacrificial donors. Generally, the use of sacrificial electron donors is not ideal as they are considered waste. Coupling acetylene photocatalytic hydrogenation with organic upgrading to produce valuable reduction and oxidation products simultaneously has never been reported so far. Here, we could substitute the TEAO sacrificial donor with benzylamine. The illumination of a reaction mixture consisting of Co-CN and benzylamine under C2H2 produces C2H4 (Figure , Supplementary Information) and N-Benzylidenebenzylamine (Figure , Supplementary Information) that is an important intermediate for the manufacture of fine chemicals, agrochemicals and pharmaceuticals. This result demonstrates a win-win strategy by coupling hydrogenation with oxidative organic synthesis in the same photocatalytic system, thus avoiding undesirably waste of energy of photogenerated holes and improve charge carrier utilization. Based on experimental results and DFT calculations we proposed a mechanism for the photocatalytic semi-hydrogenation of C2H2 using our Co-CN based system (Figure ).