A new and versatile synthetic route to a benzophenanthridine alkaloid was developed by a bond formation between C4b and N5 on the benzo[c]phenanthridine nucleus, using a microwave-assisted electrocyclic reaction of the aza 6p-electron system. This strategy was successfully used to synthesize nornitidine (1b), noravicine (1d), and isodecaline (1f).