Benzisoxazole derivatives are well known for their antipsychotic properties. Efforts were made to synthesis derivatives of 6-fluoro-3-(piperidin-4-yl) benzo[d]isoxazole (S1, S2, S3 and S4) to study their efficacy as a promising antipsychotic drug producing menial Extrapyramidal symptoms (EPS). The pathogenesis of many psychotic disorders are due to hyperactivity of central Dopamine D2 and serotonin 5HT2 receptors and antagonism against these receptors have been associated with lowering the negative symptoms and decreased tendency to cause EPS. In the present study we have investigated for D2 receptor and serotonin receptor antagonism activity by in vivo methods wherein 5-Hydroxytryptophan (5-HTP) induced head twitches and apomorphine induced climbing behaviour are analysed. Treatment of synthesized molecules (1-5mg/kg) to albino mice showed a dose-dependent decrease in the apomorphine-induced climbing behaviour and 5-hydroxytryptamine (5-HTP)-induced head twitch activities. The molecules also revealed significant results for L-dopa induced hyperactivity, Clonidine induced aggression behaviour.