Antagonist activity at the alpha 3 beta 4 nicotinic acetylcholine receptor (nAChR) is thought to contribute to the antiaddictive properties of several compounds. However, truly selective ligands for the alpha 3 beta 4 nAChR have not been available. We report the discovery and SA R of a novel class of compounds that bind to the alpha 3 beta 4 nAChR and have no measurable affinity for the alpha 4 beta 2 or alpha 7 subtype. In functional assays the lead compound antagonized epibatidine-induced Ca2+ flux in alpha 3 beta 4-transfected cells in a noncompetitive manner.