Potent and selective 5-HT7 receptor antagonist (pKi values are 8.9, 7.2 and 6.0 for 5-HT7A, 5-HT5A and 5-HT1B and < 6.0 for 5-HT1A, 5-HT1D, 5-HT1E, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT2C, 5-HT4 and 5-HT6 receptors respectively). Brain penetrant in vivo.