Nickel(II) complexes of type [Ni(L)2Cl2] and [Ni(L)2(OCOCH3)2], where L = (cyclohexyl-N-thio)-1,2-ethylenediamine (L1) and (cyclohexyl-N-thio)-1,3-propanediamine (L2) has been synthesized and characterized by elemental analysis, FT-IR, mass, UV-Vis, and 1H NMR spectroscopic studies. The thiodiamines coordinate as a bidentate N-S ligand. The ratio of the metal: ligand was 1: 2 for all the complexes. The binding sites are the azomethine nitrogen and thioamide sulfur. The complexes are found to be soluble in acetone, dimethylformamide, and dimethylsulfoxide. All the complexes were found amorphous in nature. Molar conductance values in DMSO indicate the nonelectrolyte nature of the complexes. In vitro antifungal and in vitro antibacterial studies were performed against fungal and bacterial strains, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger, and Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, respectively. Preliminary antimicrobial screening shows the good results against both the fungal and the bacterial strains, which can lead through the investigation of better drug.