Thioxanthene is a chemical compound in which the oxygen atom in xanthene is replaced with a sulfur atom. It is also related to phenothiazine. Several of its derivatives are used as typical antipsychotics in the treatment of schizophrenia and other psychoses. Thioxanthene is a chemical compound in which the oxygen atom in xanthene is replaced with a sulfur atom. It is also related to phenothiazine. Several of its derivatives are used as typical antipsychotics in the treatment of schizophrenia and other psychoses.