The invention concerns an oxidation dyeing composition for keratinous fibers containing at least a monobenzene coupling agent including at least a cationic group Z bearing at least a cyclized or non-cyclized quaternary ammonium unit, the use of said coupling agents for dyeing keratinous fibers, dyeing methods using same, and novel monobenzene coupling agents comprising at least a cationic group Z bearing at least a cyclized or non-cylized quaternary ammonium.