Butene hydrogenation activity is intimately connected with the occupied and unoccupied electronic states of gold active site. We prepare well-defined Au(III) sites in IRMOF-3 structure, and tuned the metal density-of-states by replacing the substituent group of the coordinating group at position 5. Resonant inelastic X-ray scattering experiments and theoretical calculations revealed an increase in unoccupied 5d states of Au when the substituent group is a donating group, which leads to a dramatic increase in catalytic activity.