Novel 3,6-disubstituted pyridazines were synthesized by facile method and screened for their vaso-relaxant properties utilizing isolated thoracic rat aortic rings. Compounds 8a and Ha exerted potent vasorelaxant activity (IC50 = 198 and 177 mu M, respectively) relative to doxazosin mesylate (used reference standard, IC50 = 226 mu M), that, they may represent promising hits for treatment of cardiovascular disorders. The observed activity was validated by a statistically significant QSAR model (N = 32, n = 6, R-2 = 0.811782, R-cvOO(2) = 0.7153, R-cvMO(2) = 0.7209, F = 17.9708, s(2) = 9.65226 x 10(-8)) that was obtained employing CODESSA-Pro software. (C) 2015 Elsevier Masson SAS. All rights reserved.