The development of low-cost molecular electrocatalysts for the ER from water remains scarce. The efficient electrocatalytic hydrogen volution reactions (HER) with a series of sterically encumbered carbene igated silver(I), gold(I) and nickel(II) complexes established here demonstrate he potential of molecular catalyst in hydrogen production from water. Tuning he benzannulation on the coumarin-substituted N-heterocyclic carbene (NHC) ligands afforded six new silver(I) (5-10), two new gold(I) (11 and 2), and two reported nickel(II) (13 and 14) NHC complexes, which differ by he steric bulk around the metal atom and the counterion. Benefiting from the esirable structure and appropriate porous morphology, complexes 6, 9, 10, and 11 exhibited significant electrocatalytic HER activity in acidic medium with n overpotential of-226.4,-445,-243 and-310 mV vs RHE, respectively, to rive a current density of 10 mA/cm2 when immobilized on glassy carbon lectrode, which is analogous to that of several transition metal-based anomaterials. The kinetic parameters such as Tafel slope value and exchange current density for the active complexes and the ormer observation authenticated the Volmer-Heyrovsky mechanism. Theoretical studies advocate the potential of developing novel eries of carbene-ligated HER electrocatalysts based on the controlled ligand field following scalable and viable protocols.