bonding and the back bonding process which implies that the bonding-back-bonding is not simultaneous events for this reaction. These findings ameliorate the DFT-based designing of heterocyclic carbenes to model a congenial catalyst for the sequestering of atmospheric nitrogen and its metamorphosis to ammonia at an ambient and metalfree condition. It is also brought to light that the optical absorption behavior of a molecule may change along the reaction path. Though molecular nitrogen, model carbene and the carbene-N 2 adduct are non-responsive to visible light, an evanescent optical absorbance in the visible region is observed during the chemical reaction.