Overall, the photocatalytic strategies described here avoid the use of noble metal catalysts, high temperatures and pressures, and H2 gas feed, all while achieving significantly higher selectivity than the current industry standard. This work is a significant step forward for the photocatalytic production of polymer-grade ethylene in molecular and porous catalysts. We anticipate that this work will stimulate further exploration into photo-and electro-catalytic activity of cobaloximes and MOF-based systems for the semi-hydrogenation of acetylene to ethylene and their integration into flow cells for crude ethylene purification, as well as motivate its use for other selective hydrogenation reactions and other alkyne substrates.