The development of new therapies to treat hypertension effectively is currently an intensive area of research. To achieve this objective quantitative structure activity relationship (QSAR) study was carried out on a reported series of phthalazine derivatives as alpha-1d antagonist, as it provides the rationale for the changes in the pharmacophore to have more potent and less toxic analogue. In this article, we report 2D and 3D QSAR studies for the set of 20, alpha-1d antagonist. A simple and convenient procedure has been developed for the synthesis of Novel 1 phthalazinone and 1, 4phthalazinedione derivatives using Schotten–Baumann reaction and Gabriel Michael reaction respectively. All compounds have been characterized by IR, NMR,and MASS spectroscopy.