Benzene rings of N-alkyltoluidine and benzene (or iodobenzene) in acetic acid were annelated with acetylenedicarboxylates by palladium(II) acetate to give N-alkylindole-2,3-dicarboxylate and naphthalene-1,2,3,4-tetracarboxylate. The formation of the products are explained in terms of toluidine radical cation intermediates.