An unprecedented efficient methodology for the synthesis of 10,11-dihydro-10-oxo-5Hdibenz[b,f]azepine via a three new synthetic pathways is described. The key steps of this approach are based on classical Friedel-Craft ring closures of three precursors 1-(2-(N-phenyl-Ntosylamino)phenyl)-2-bromoethanone, ethyl 2-(2-(N-phenyl-N-tosylamino)phenyl)acetate or 2-(2-(N-phenyl-N-tosylamino)phenyl)acetic acid, by using AlCl3/CH3NO2 or AlCl3 in dichloromethane. For the latter two precursors, P2O5 in toluene worked also well. The precursors were easily obtained in a two- or three -step reaction sequence. Overall, the described approach allows easy and efficient access to the tricyclic dibenzoazepinone ring system from easily accessible starting materials.