2-Acyl-1,4-naphthoquinones react with 3,4,5-trimethoxyaniline, under aerobic conditions, to give benzophenanthridinequinone, benzocarbazole and 2-acyl-3-(3,4,5-trimethoxyanilino)-1,4-naphthoquinone derivatives. The formation of the heterocyclic compounds is discussed in terms of the ring closure of C-C Michael type adduct intermediates through two alternative N-C-bond formations. The propensity of the substrates to undergo preferential C-C instead of C-N bond formation and the further heterocyclization of the C-C Michael type adduct intermediates is rationalized by using product stability parameters assessed by DFT calculations. Preliminary results are reported on a convenient access towards 2-acyl-3-(3,4,5-trimethoxyanilino)-1,4-naphthoquinones from 2-acylnaphthoquinones and their cytotoxic activities on cancer cells.