A new metallocomplex with antitumor activity fabricated from ditopic bis(1-(pyridin-2-yl)-methylidene)carbazide and Cd(NO3)2

• Synthesis and structure of a novel Cd(II) complex with bis(1-(pyridin-2-yl)-methylidene)carbazide ligand. • Single-crystal X-ray diffraction reveals a 3D supramolecular framework stabilized by noncovalent interactions. • QTAIM and NCIplot analyses provide insights into crystal stabilization via noncovalent interactions. • Cadmium complex exhibits selective cytotoxicity against breast and liver cancer cell lines. This study reports the structural analysis and antitumor properties of a new dinuclear heteroleptic discrete Cd(II) complex, [Cd 2 (H 2 L)(NO 3 ) 3 (H 2 O) 3 ]NO 3 ( 1 ), synthesized through the reaction of Cd(NO 3 ) 2 ·4H 2 O with bis(1-(pyridin-2-yl)-methylidene)carbazide ( H 2 L ). The asymmetric unit of 1 comprises two dinuclear heteroleptic [Cd 2 (H 2 L)(NO 3 ) 3 (H 2 O) 3 ] + cations and two NO 3 − anions. Each [Cd 2 (H 2 L)(NO 3 ) 3 (H 2 O) 3 ] + cation features two distinct coordination polyhedra: [Cd(N^N′^O)(NO 3 ) 2 (H 2 O)] and [Cd(N^N′^O)(NO 3 )(H 2 O) 2 ] + (N^N′^O = one chelating pendant arm of H 2 L ). Notably, the coordinated NO 3 − anions exhibit either bidentate or anisobidentate coordination modes. The crystal structure of 1 is stabilized by a range of intermolecular interactions, including O–H⋯O, N–H⋯O, and π⋯π interactions. Additionally, antiparallel NO⋯NO interactions involving the coordinated nitrato ligands were identified and confirmed using NCIplot and QTAIM computational tools. The cytotoxic and antiproliferative effects of 1 , as well as its inhibition of colonization and metastasis in the MCF-7, Huh7, HCT-116, and A549 cell lines, were investigated. While H 2 L exhibited no cytotoxicity, complex 1 demonstrated cell-killing activity, with IC 50 values of 17.05 µM for MCF-7, 14.02 µM for Huh7, and 27.27 µM for HCT-116 cells. In addition, 1 increased the expression of the DNA damage response protein p21 in HCT-116 cells. A549 cells showed lower sensitivity to 1 compared to the other cell lines examined in this study.