Most ligand design studies for reactions catalyzed by (NHC)Cu-H (NHC = N-heterocyclic carbene ligand) have focused on introducing steric bulk near the Cu center. Here, we evaluate the effect of remote ligand modification by examining a series of [(NHC)CuH]2 in which the para substituent (R) on the aryl groups ofthe NHC is Me, Et, tBu, OMe or Cl. Although the R group is distant (6 bonds away) from the reactive Cu-H center, the complexes exhibit different spectroscopic features and reactivity. DFT calculations provide a rationale for the observation that although the solid-state structures of the complexes are similar, their UV-Visible and 1H NMR spectra in solution differ significantly. Furthermore, kinetics studies of the insertion of ketone, imine, alkyne, and unactivated a-olefin substrates reveal that (NHC)Cu-H complexes with bulky or electron-rich R groups undergo faster substrate insertion. Analysis of the kinetics data suggests that this effect is predominantly caused by destabilization of the [(NHC)CuH]2 dimer relative to the (NHC)Cu-H monomer, thus kinetically favoring the formation of Cu-H monomer. These results indicate that remote functionalization of NHCs is a compelling strategy for improving the reactivity of Cu-H species.