The present study focused on the synthesis, preliminary pharmacological screening and acute toxicity testing of novel series of 7-(2-(benzo[d]thiazol-2-ylamino)ethoxy)-4-methyl-2H-chromen-2-one derivatives (4a-4k). This novel series was designated and synthesized by refluxing 2-amino benzothiazoles substituted derivatives (3a-3k) with 7-(2-chloroethoxy)-4-methyl-2H-chromen-2-one (2) in dry pyridine. All the synthesized compounds were screened and evaluated for dopamine D2 and serotonin 5HT2 antagonistic activity as a measure of atypical antipsychotic property. Compounds 4b, 4c, 4e, 4g and 4i have shown good preliminary pharmacological activity and these compounds were subjected to acute toxicity (lethal dose) studies for determining effective dose range using probit log scale method. The therapeutic index of the selected compounds was determined to compare with other series of compounds to select better active compound(s). The structures of all compounds were confirmed using spectral studies. All the synthesized compounds showed good dopamine D2 and serotonin 5HT2A receptor antagonist activity, which could indicate atypical antipsychotic activity. Compounds (4e) and (4b) with electron withdrawing substituents showed better atypical antipsychotic activity.