Here we report, for the first time, an extensive characterization of an N-heterocyclic carbene (NHC)-modified supported heterogeneous catalyst. The existence of the metal-carbene bond could be proven by C-13-SS-NMR experiments. Furthermore, it could be shown that the modification with NHCs does not structurally change the catalyst itself. The effect of the nature and the loading of the NHC on the activity and selectivity of the heterogeneous catalyst is presented by a hydrogenation study, finally leading to an NHC-enabled tunable heterogeneous catalyst for chemoselective hydrogenation.