A new series of 1,3,5-triaryl-4,5-dihydro-1 H -pyrazole 10a – l was designed and synthesized via cyclization of chalcones 8a – f with 4-amino/methanesulfonylphenylhydrazine hydrochloride 9a – b . All the synthesized compounds were evaluated for their cyclooxygenase (COX) inhibition, anti-inflammatory activity, ulcerogenic liability and analgesic activity. All compounds were more COX-2 inhibitors than COX-1. While most compounds showed good anti-inflammatory activity, the trimethoxy derivatives ( 10a , 10b, 10g and 10h ) were the most potent derivatives (ED 50 = 55.78, 53.99, 67.65 and 69.20 μmol/kg respectively) in comparison with celecoxib (ED 50 = 82.15 μmol/kg). Compounds 10a , 10b, 10g and 10h (ulcer index = 2.68, 1.20, 2.63 and 2.66 respectively) showed less ulceration effect than celecoxib (ulcer index = 2.90). Also, Compounds 10a , 10b, 10g and 10h showed analgesic activity higher than celecoxib and comparable to that of ibuprofen. In addition, molecular docking studies were performed for compounds 10a , 10b, 10g and 10h and the results were in agreement with that obtained from the in vitro COX inhibition assays. [ABSTRACT FROM AUTHOR]