Crystal structure, Hirshfeld surface and crystal void analysis of (1 <i>Z</i> )-1-[( <i>E</i> )-2-(2 <i>H</i> -1,3-benzodioxol-5-ylmethylidene)hydrazin-1-ylidene]-1,2-dihydrophthalazine

The title com-pound, C₁₆H₁₂N₄O₂, crystallizes in the tetra-gonal space group <i>I</i>4₁/<i>a</i> with one mol-ecule in the asymmetric unit. The 2<i>H</i>-1,3-benzodioxole ring is almost planar [maximum deviation of -0.039 (3) Å] and makes a dihedral angle of 11.25 (5)° with the 1,2-di-hydro-phthalazine moiety. An intra-molecular N-H⋯N hy-dro-gen bond stabilizes the mol-ecular conformation. Inter-molecular N-H⋯N hy-dro-gen bonds, as well as C-H⋯N hy-dro-gen bonds, lead to the formation of supra-molecular chains extending parallel to [001]. The inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter-actions contribute most to the crystal packing (37.4%). The volume of the crystal voids and the percentage of free space were calculated to be 614.55 ų and 11.5%, respectively.