The invention relates to 5-HT receptor agonists or antagonists. Novel arylpiperazinyl sulfonamide compounds represented by Formulae I: and II, and synthesis and uses of those compounds for treating diseases including those mediated directly or indirectly by 5-HT receptors, are disclosed. Such conditions include central nervous system disorders such as generalized anxiety disorder, ADD/ADHD, neural injury, stroke, and migraine. Methods of preparation and novel intermediates and pharmaceutical salts thereof are also included.