Aseries of novel benzimidazole-2-carboxylic acid amides and esters with a quinuclidine or a tropane moiety were synthesized and evaluated for in vitro affinity for the 5-HT3, 5-HT4 and D2 receptors. Compounds 15a, 13j and 13h exhibited affinity for the 5-HT3 receptor (Ki= 20.2, 18.4 and 12.7 nM, respectively) and no significant affinity for both 5-HT4 and D2 receptors. The amide-ester replacement did not induce significant changes in the affinity ...