The post-transition diamagnetic complex of Cd(II) with benzimidazole ('N' Donor) and nitrite ion ( nitrito-O, 'O' Donor) heteroatom ligands were synthesized and characterized by elemental analysis, estimation of metal ion, conductance (10 -3 M complex solution), UV-Visible, IR, Far-IR, NMR spectra, SEM and X-ray diffraction (single crystal method). The complex was crystallized in orthorhombic P212121 space group having a = 8.8701(3) Å,b = 11.5026(4) Å and c = 22.5665(8) Å. The interfacial angle of crystal are α = β = γ = 90°, volume and density of the crystallized complex were 2302.44(14) Å 3 and 1.612 mg/m 3 respectively. Cd(II) ion is surrounded by two oxygen atom of nitrite ion and three nitrogen atom of benzimidazole by distorted pentagonal bipyramidal structure. SEM images of the crystal also discussed the morphology. Biological activities against bacterial and fungal strains viz., Klebsiella pnemoniae and salmonella typhi (gram-negative bacteria), Bacillus subtilis (gram-negative bacteria) and pathogenic yeast C. albicance were carried out by Agar well diffusion method. On comparing benzimidazole the complex crystal shows potent activities against tested microorganisms.