A series of N-(1-ethyl-4-methylhexahydro-1, 4-diazepin-6-yl) nicotinamide derivatives were prepared and evaluated for their binding to 5-HT3 and dopamine D2 receptors. Among them, the 5-bromo-2-methoxy-6-methylaminonicotinamide 16 and its (R)-isomer were found to have potent affinities for both receptors. The affinities of (R)-16 for 5-HT3 and dopamine D2 receptors are approximately 3-fold higher than those of the corresponding benzamide ...