The enantiomers of N-(quinuclidin-3-yl)-4-amino-3-chloro-1,8 naphthalimide (3) were examined for interactions at 5-HT3 and 5-HT4 receptors. (R)-3 was found to be a potent 5-HT3 receptor antagonist while (S)-3 was found to be a 5-HT4 receptor agonist with reduced 5-HT3 receptor affinity.