Abstract The synthesis of 4‐substituted 5 H ‐dibenz [ b, f ] azepines and 10, 11‐dihydro‐5 H ‐dibenz [ b, f ] azepine resulting from the reaction of the corresponding 4, 5‐dilithio derivatives and different N, N ‐dimethylamides is reported. The total assignment of the pmr spectra of the prepared formyl derivatives based on decoupling experiments is also described.