Two new Cu(II) coordination polymers, [Cu(L)(NCS)]n (1) and [Cu(L)Cl(H2O)]n·nH2O (2), were synthesized from CuCl2·2H2O and N′-(pyridin-2-ylmethylene)nicotinohydrazide (HL) in the presence and absence of ammonium thiocyanate (NH4SCN), respectively, in good yields. Both complexes were systematically characterized using spectroscopic methods (elemental analysis, FT-IR, and mass spectrometry) and single-crystal X-ray diffraction. The crystallographic studies confirmed their polymeric nature and monoclinic crystal system, but with distinct space groups: P2₁/c for 1 and P2₁/n for 2. Structural analysis revealed that the Cu(II) centre in 1 adopts a distorted square pyramidal geometry, whereas in 2, it exhibits a distorted octahedral geometry. Hirshfeld surface (HS) and 2D fingerprint plot analyses were employed to examine non-covalent intermolecular contacts within the crystal lattice. DFT analysis revealed that complexation is more favoured in 1 compared to 2. An evaluation of anticancer activity was carried out by examining the cytotoxicity of 1, 2, and the ligand (HL) on Dalton’s Lymphoma (DL) cells. Additionally, their cytotoxicity was also assessed on healthy peripheral blood mononuclear cells (PBMCs) to determine potential effects on non-cancerous cells.
