Molybdenum–carbamate complex bearing a pyridine-based 2,6-bis(di-tert-butylphosphinomethyl)pyridine (PNP)-pincer ligand is synthesised from the reaction of a molybdenum–nitride complex with phenyl chloroformate. The conversion between the molybdenum–carbamate complex and the molybdenum–nitride complex under ambient reaction conditions is achieved. The use of samarium diiodide (SmI2) as a reductant promotes the formation of cyanate anion (NCO−) from the molybdenum–carbamate complex as a key step. Based on the stoichiometric reactions, we have demonstrated a synthetic cycle for NCO− from dinitrogen mediated by the molybdenum–PNP complexes in two steps. Based on this synthetic cycle, we have achieved the catalytic synthesis of NCO− from dinitrogen under ambient reaction conditions. We believe that these results described in this manuscript provide valuable information to achieve the catalytic transformations of dinitrogen into valuable organonitrogen compounds under ambient reaction conditions.