The present work was aimed to synthesize eight new diphenylamine derivatives by the reactions of 2-chloro-N-(4-(diphenyl amino) thiazol-2-yl)acetamide with substituted phenols in the chloroform along with anhydrous potassium carbonate and potassium iodide. The structures of newly synthesized compounds were characterized by IR, NMR, Mass and elemental analysis techniques. Toxicity profile (acute and subacute oral toxicity) and biological activity (analgesic and anti-inflammatory activity) of the synthesized derivatives was performed. Findings of the present work suggested that the synthesized compounds may be one of the excellent potent compounds to treat pain and inflammation. Therefore compounds of this group especially AK-4 (N-(4-(diphenylamino)thiazol-2-yl)-2-(2- nitrophenoxy)acetamide) could be an excellent starting point to build up new lead compounds in the management of pain and inflammation.