A new method for the preparation of the pyrrolo [2, 3-b] quinoline ring system involving the sequential formation of the pyridine ring (electrocyclic ring-closure) and the pyrrole (nitrene insertion reaction) rings. This approach is based on the regioselective formation of the iminophosphorane 2 from the bis (azide) 1, followed by aza Wittig reaction with isocyanates and further thermal treatment.