A series of novel 2-[(2-aminophenyl)imino]imidazolinium salts 3a-d and N-benzyl-N-(4,5-dihydro-imidazol-2-yl)-O-methylhydroxylamine hydrochloride 7a-c were prepared and their structure was determined by IR and NMR spectroscopic data as well as X-ray analysis of the imidazolinium azide salt 3e. Binding evaluation for both alpha 1- and alpha 2-adrenergic receptors in rat brain preparations of these compounds and the previously described alpha-hydroxy-2-aryliminoimidazolines 11a-d, N-(4,5-dihydroimidazol-2-yl)-1,3-2-oxodihydrobenzimidazoles 12a-b, 2-amino-N-(4,5-dihydroimidazol-2-yl)-benzimidazoles 13a-b, and N-(4,5-dihydroimidazol-2-yl)-indoles 14a-b was performed. Among the compounds tested, 2-[(2-amino-4,5-dichlorophenyl)imino]imidazolinium chloride 3c showed highest binding affinity to alpha 2-adrenoreceptors (Ki = 30 nM).