Some new 7-substituted-phenyl-3, 4, 8, 9-tetrahydro-2 H-pyridazino [1, 6-a][1, 3, 5] triazin-2- imine/one/thione derivatives were synthesized by a sequence of reactions starting from appropriate aryl hydrocarbons. The final compounds were screened for antihypertensive activities by non-invasive method using Tail Cuff method. All the test compounds showed significant antihypertensive activity; 7-(biphenyl-4-yl)-3, 4, 8, 9-tetrahydro-2 H-pyridazino [ ...