One route to address climate change is converting carbon dioxide to synthetic carbon-neutral fuels. Whereas carbon dioxide to CO conversion has precedent in homo- and heterogeneous catalysis, deoxygenative coupling of CO to products with C C bondsas in liquid fuels-remains challenging. Here, we report coupling of two CO molecules by a diiron complex. Reduction of Fe-2(CO)(2)L (2), where L2- is a bis(ss diketiminate) cyclophane, gives [K(THF)(5)][Fe-2(CO)(2)L] (3), which undergoes silylation to Fe-2(CO)(COSiMe3)L (4). Subsequent C-OSiMe3 bond cleavage and C=C bond formation occurs upon reduction of 4, yielding Fe-2(mu-CCO)L. CO derived ligands in this series mediate weak exchange interactions with the ketenylidene affording the smallest J value, with changes to local metal ion spin states and coupling schemes (ferro- vs. antiferromagnetism) based on DFT calculations, Mossbauer and EPR spectroscopy. Finally, reaction of 5 with KEt3BH or methanol releases the C2O2- ligand with retention of the diiron core