BACKGROUND: Novel antipsychotics are characterized by multitarget profile of action, affecting among others, dopamine and serotonin receptors. In a series of experiments, we designed, synthesized and examined two new isoquinoline-sulfonamide analogs of the modern multitarget antipsychotics aripiprazole and brexpiprazole, compounds PZ-1262 and PZ-1264. We hypothesized that the 4-isoquinolinesulfonamide moiety, derived from the structure of 5-HT METHODS: The receptor binding profile, functional activity, and metabolic stability of PZ-1262 and PZ-1264 were evaluated through in vitro assays. Potential antipsychotic, antidepressant, anxiolytic, and pro-cognitive effects were assessed using in vivo behavioral tests in rodents. RESULTS: In vitro, PZ compounds demonstrated partial agonistic activity at 5-HT CONCLUSIONS: The complex pharmacodynamic profile translated into the useful psychotropic effects. While the compounds potentiated D-amphetamine- and phencyclidine-induced hyperactivity, this action could be regarded as a desired activating effect rather than evidence against antipsychotic-like efficacy. Present findings point to PZ-1262 as a more promising lead compound for further research.