The reaction of alkyl halides with 2-(arylimino) imidazolidines (I) leads to imidazoline derivatives 11, in which the side chain is situated at the bridge nitrogen atom between the phenyl group and the imidazoline ring. The new imidazolines (11) exert a specific bradycardic action at a cardiac site. Syntheses and pharmacology are shown and structure- activity relationships discussed. The results reveal that the imidazoline derivatives (11) ...