Abstract: Background: Imidazole derivatives are reported to possess wide spectrum of pharmacological activities. This study describes the pharmacological and toxicological studies of five imidazole derivatives namely IMZ1: 2-phenyl-4,5-diphenyl imidazole, IMZ2: 2-[4-methoxyphenyl]-4,5-diphenyl imidazole and IMZ3: 2-[2-nitrophenyl]-4,5-diphenyl imidazole, IMZ4: 2-[4-N,N-dimethylaminophenyl]-4,5-diphenyl imidazole, IMZ5: 2-[3-methoxyphenyl]-4,5-diphenyl imidazole derivatives. Result: Analgesics, anti-inflammatory, antipyretic, anticonvulsant studies of imidazole derivatives at 400 mg kg-1, p.o. have shown significant activity as compared to control. Tail-flick method and acetic acid induced writhing test was used to screen analgesic activity. Carrageenan induced rat paw edema model and Freund’s adjuvant-induced polyarthritis model was used to assess the anti inflammatory activity. Amongst five imidazole derivatives, IMZ5 was found to be more active. Based on the result of pharmacological studies, IMZ5 was selected for toxicological studies by Up and Down Procedure. Acute toxicity studies revealed that 2-[3-methoxyphenyl]-4, 5-diphenyl imidazole derivatives are non toxic in rats up to 5000 mg kg-1, p.o. The sub acute toxicity study of IMZ5 showed that slight alteration in Hb content, RBC and WBC count. In biochemical analysis, level of blood glucose and bilirubin reduced to some extent where as AST, ALT and ALP level elevated. Histopathological studies revealed that there was mild toxicity on liver and kidney at 1000 mg kg-1, p.o but no toxic effects were observed on heart. Conclusion: All the tested derivatives retained the above mentioned pharmacological activities due to the basic imidazole heterocycle. Since, there was mild toxic profile on this nucleus, further structural exploitation may yield safe therapeutic drug candidates.