The main objective present research work to synthesis, characterization and biological evaluation of pyridazine analogues. To study the different synthesized derivative by using different analytical parameters like IR, Mass and NMR analysis. And also find out the antihypertensive activity. The studies on the hydralazine group drugs led to the synthesis of many pyridazinone derivatives with a wide activity spectrum on cardiovascular system. Pyridazinone derivatives, a class of compounds containing the N-N bond, exhibit a wide range of pharmacological activities such as antidepressant, antihypertensive, and cardiotonic etc.Some 6-(substituted phenyl)-2-(substituted methyl)-4,5-dihydropyridazin-3(2H)-one derivatives were synthesized by reacting 6-Phenyl substituted 2,3,4,5-Tetrahydro pyridazin-3-one with cyclic secondary amine under Mannich reaction conditions. The final compounds (vj1-vj15) were evaluated for antihypertensive activities by non invasive method using Tail Cuff method. The current work describes the synthesis of pyridazinone derivatives with encouraging in vivo antihypertensive activity by non-invasive method using Tail Cuff method. Compound number vj8, and vj12 were found to show highly significant reduction in mean arterial blood pressure. The current work describes the synthesis of pyridazinone derivatives with encouraging in vivo antihypertensive activity by non-invasive method using Tail Cuff method.