Two first representatives, 5 and 6, of the still unknown 4, 5-bis (dimethylamino) quinoline have been synthesized and studied. While the former, being protonated either at the peri- NMe2 groups or at the ring nitrogen, has been shown to display properties of both a proton sponge and azine, its counterpart 6 behaves exclusively as azine giving only a quinolinium salt.
