The use of hydride species for substrate reductions avoids strong reductants, and may enable nitrogenase to reduce multiple bonds without unreasonably low redox potentials. In this work, we explore the N=N bond cleaving ability of a high-spin iron(II) hydride dimer with concomitant release of H-2. Specifically, this diiron(II) complex reacts with azobenzene (PhN=NPh) to perform a four-electron reduction, where two electrons come from H-2 reductive elimination and the other two come from iron oxidation. The rate law of the H-2 releasing reaction indicates that diazene binding occurs prior to H-2, elimination, and the negative entropy of activation and inverse kinetic isotope effect indicate that H-H bond formation is the rate-limiting step. Thus, substrate binding causes reductive elimination of H-2 that formally reduces the metals, and the metals use the additional two electrons to cleave the N-N multiple bond.