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. And also to find out the good pharmacologically active synthesized compounds. 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, antithrombotic, anticonvulsant, cardiotonic, anti HIV and anticancer etc. All the synthesized compounds were obtained in good yield by optimizing various synthetic procedures. The structures of the compounds were established by elemental analysis, IR, ¹H-NMR and Mass spectral data analysis. The current work describes the synthesis of some new substituted pyridazine derivatives with encouraging antihypertensive activity by non-invasive method using Tail Cuff method. Some new dihydropyridazinone analogues were synthesized by a sequence of reactions starting from respective aryl hydrocarbons. Pyridazinone derivatives were synthesized under different reaction mechanism like Fredal craft acylation for substituted benzene, Claisen condensation and Manich reaction conditions. Total Ten compounds (4a-4i) were synthesized by mentioned scheme. The final compounds 4e and 4i were evaluated for antihypertensive activities by non-invasive method using Tail Cuff method. Compound 4e and 4i were found to show highly significant reduction in mean arterial blood pressure but at higher dose in comparison to standard drugs.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. And also to find out the good pharmacologically active synthesized compounds. 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, antithrombotic, anticonvulsant, cardiotonic, anti HIV and anticancer etc. All the synthesized compounds were obtained in good yield by optimizing various synthetic procedures. The structures of the compounds were established by elemental analysis, IR, ¹H-NMR and Mass spectral data analysis. The current work describes the synthesis of some new substituted pyridazine derivatives with encouraging antihypertensive activity by non-invasive method using Tail Cuff method. Some new dihydropyridazinone analogues were synthesized by a sequence of reactions starting from respective aryl hydrocarbons. Pyridazinone derivatives were synthesized under different reaction mechanism like Fredal craft acylation for substituted benzene, Claisen condensation and Manich reaction conditions. Total Ten compounds (4a-4i) were synthesized by mentioned scheme. The final compounds 4e and 4i were evaluated for antihypertensive activities by non-invasive method using Tail Cuff method. Compound 4e and 4i were found to show highly significant reduction in mean arterial blood pressure but at higher dose in comparison to standard drugs.