A nickel(II) complex, [NiL(phen)2]L·5H2O (HL = 2-phenyl-4-selenazole carboxylic acid, C10H7O2NSe, phen = 1,10-phenanthroline), was synthesized and characterized by elemental analysis and IR. The single crystal structure was determined by single-crystal X-ray diffraction. C88H78N12Ni2O19Se4crystallized in the triclinic system, space groupPī. The interaction between the complex and the calf thymus DNA was studied by an ethidium bromide fluorescent probe. The antibacterial activities of the complex and ligand against five species of bacteria,Escherichia coli,Staphylococcus epidermidis,Streptococcus viridans,Staphylococcus aureusandAcinetobacter baumanii, were tested. The anticancer activities of the complex against human pancreatic cancer line PANC-28 and human hepatocarcinoma line HuH7 were also studied by employing an MTT assay. [ABSTRACT FROM AUTHOR]