Compound 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo dthiazol-2-yl)methylene)thiazol-2-amine (3c) was shown great anti-inflammation, analgesic, Ulcerogenic, Acute toxicity and free radical scavenging action as compare to reference drugs in albino rats at a dose of 50 mg/kg p.o. Display omitted •Oxazole substitutents were found to be less biologacally active.•Compound 3a-3d had more inhibition potential than 3a′-3d′.•Compound 3c was the most anti-inflammatory and analgesically active.•Chloro substituted derivatives were found to be more effective than other. Non-Steroidal biologically active heterocyclic compounds 4-(2-(4-chlorophenyl) benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzodthiazol-2-yl)methylene) thiazol-2-amine (3a-3d), 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted − 2-hydrobenzo dthiazol-2-yl)methylene)oxazol-2-amine (3a′-3d′), (Z)-N'-(4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)thiaol-2-yl)-N-(4-substituted phenylimino)-3-substituted-2-hydrobenzodthiazole-2-carboxamidine (4a-4 h) and (Z)-N'-(4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)oxazol-2-yl)-N-(4-substituted phenylimino) − 3-substituted-2-hydrobenzodthiazole-2-carboxamidine (4a′-4h′) were synthesized starting from 2-chloro-1-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl) ethanone (1). The structure configuration of newly synthesized compounds has been determined by elemental analysis and various spectroscopic (IR, 1HNMR and GCMS) techniques. These compounds were tested for their anti-inflammation, analgesic, ulcerogenic, acute toxicity and free radical scavenging action and compared with reference drugs in albino rats. Compound 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo dthiazol-2-yl)methylene)thiazol-2-amine (3c) was the most active compound than reference drug at a dose of 50 mg/kg p.o.