Disclosed herein are para-phenylenediamine compounds of formula (I), and their salts and solvates: ##STR00001## wherein R.sub.1 and R.sub.2 form, together with the carbon atoms to which they are attached, a 4-, 5-, 6- or 7-membered ring, wherein the ring comprises carbon atoms and, optionally, one or two atoms chosen from oxygen and nitrogen, the ring being optionally substituted, with the proviso that when the ring comprises two atoms chosen from oxygen and nitrogen, these two atoms are non-adjacent. Compositions comprising these compounds and processes of making them, as well as processes and kits for dyeing keratin fibers are also disclosed.