Solvent-extracted nitrogenase cofactors can reduce C-1 substrates (CN-, CO and CO2) to hydrocarbons in reactions driven by a strong reductant, SmI2 (E-0' = 1.55 V vs SCE). Here we show that a synthetic [Et4N](4)[Fe6S9(SEt)(2)] cluster (designated the Fe-6(RHH)-cluster), which mimics the homometallic [Fe8S9C] core of the nitrogenase cofactor (designated the L-cluster), is capable of conversion of C-1 substrates into hydrocarbons in the same reactions. Comparison of the yields and product profiles between these homometallic clusters and their heterometallic counterparts points to possible roles of the heterometal, interstitial carbide and belt sulfur-bridged iron atoms in catalysis. More importantly, the observation that a "simplified", homometallic cofactor mimic can perform Fischer-Tropsch-like hydrocarbon synthesis suggests future biotechnological adaptability of nitrogenase-based biomimetic compounds for recycling C-1 substrates into useful chemical and fuel products.