(S)-SCQ1 is a drug which acts as a potent and selective antagonist for the 5-HT<sub>2B</sub> and 5-HT<sub>2C</sub> serotonin receptors, but with only modest affinity for the closely related 5-HT<sub>2A</sub> receptor and other targets such as 5-HT<sub>7</sub>. Since most currently available 5-HT<sub>2</sub> class ligands have relatively poor selectivity and bind to all three subtypes, the selectivity of (S)-SCQ1 is expected to be useful for studying 5-HT<sub>2A</sub> receptor mediated responses in the absence of 5-HT<sub>2B</sub> and 5-HT<sub>2C</sub> activation.