Abstract An iridium catalyst–stabilized by an anionic P, N ligand–was used for the symmetrical and unsymmetrical monoalkylation of para-, meta-, and ortho- benzenediamines. Benzyl and aliphatic alcohols were used as alkylating reagents. 28 derivatives were synthesized. 14 of them are new compounds. Furthermore, the alkylation of the pharmacological important diamine Dapson®(dapsone) is described. 14 dapsone ...