In the past few years there has been growing interest in using heterometallic complexes for H2 activation. Transition metal complexes supported by Lewis-acidic B, Mg, Al, Zn, and Sn ligands have all been documented to react with H2 under thermal conditions. Despite the rapid growth of this area, examples of photolytic H2 splitting using these types of heterometallic complexes are rare. To the best of our knowledge, photolytic reactivity is limited to a single example involving the addition of H2 to a Ru-Zn heterometallic complex. These findings contrast the rich chemistry of single-site transition metal complexes, where examples of photochemical H2 activation are more common. Under photolytic conditions, 18electron transition metal carbonyl complexes are prone to ligand dissociation to generate coordinatively unsaturated intermediates that can react with H2. For example, irradiation of mixtures [M(CO)6] and H2 at low temperature leads to the formation of the corresponding dihydrogen complexes [M(CO)5( 2 -H2)] (M = Cr, W). In contrast, photochemical reaction of [Ru(CO)3(PPh3)2] with H2 leads to oxidative addition to form [Ru(CO)2(PPh3)2(H)2]. Bimetallic transition metal carbonyl complexes such as [Ru( 5 -C5H5)(CO)2]2 also react with H2 under photochemical conditions. In these cases, photolysis can promote either dissociation of CO or homolysis of the metal-metal bond forming 17-electron species. As a result, a diverse set of mechanistic pathways involving both neutral and radical intermediates are possible for H2 splitting. In this paper, we report the reaction of a heterometallic Zn-Fe carbonyl complex with H2 under photochemical conditions; this is an uphill, light-driven reaction (ΔG°298K= +14.9 kcal mol -1 ).