[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] ... A systematic study of the reaction of 1,4-dihydrazinophthalazine (DHPH) with 1,3-dicarbonyls [viz., acetylacetone (acac), dibenzoylmethane (bzbz), and 1-benzoylacetone (bzac)] varying the reaction conditions was carried out to obtain the phthalazine ...