L O N Ph Ph N C H N ZnBr2 RT CdI2 RT A Zn(II), Cd(II) and Ag(I) mononuclear complexes of an N 3 O Schiff base have been synthesized. The crystal structures of these complexes have been determined. The complexes have antibacterial activity against the bacteria K. pneumoniae 114, E. coli K88, S. typhi ATCC 34, B. subtilis UC564, and S. aureus ATCC25923 and antifungal activity against A. niger, A. oryzae, P. notatum, and S. cerevisiae. An N 3 O Schiff base (L), 1 : 1 condensate of benzil monohydrazone and 4-pyridine carboxaldehyde, and its Zn(II), Cd(II), and Ag(I) complexes were synthesized and characterized by elemental analyses and various spectroscopic techniques. The crystal structures of [ZnL 2 Br 2 ] (1), [CdL 2 I 2 ]·CH 2 Cl 2 ,(2)·CH 2 Cl 2 , and [Ag(L) 2 ]ClO 4 (3) have been determined using X-ray crystallography. The Zn(II) and Cd(II) complexes show a tetrahedral configuration whereas in the asymmetric unit of 3, two independent coordination units of Ag(I) are present. Carbonyl-silver interaction, weak C-H⋯O interaction, and also π-π interaction are present in 3 in the solid state. The synthesized complexes have antibacterial activity against Klebsiella pneumoniae 114, Escherichia coli K88, Salmonella typhi ATCC 34, Bacillus subtilis UC564, and Staphylococcus aureus ATCC25923. The results showed that in some cases the antibacterial activities of the complexes were comparable to standard antibiotics Tetracycline and Streptomycin. The antifungal activities of the complexes were also studied for Aspergillus niger, Aspergillus oryzae, Penicillium notatum, and Saccharomyces cerevisiae. MIC values of 1, 2·CH 2 Cl 2 , and 3 are less than the Nystatin standard.