The significance of thiosemicarbazone and their complexes, apart from their diverse chemical and structural characteristics, stems from not only their potential but also their proved application as biologically active particles. The full application and structural diversity of complexes of thiosemicarbazone prompted us to synthesize the tridentate NNO- donor thiosemicarbazones and their complexes. Due to good chelating ability, the present work is mainly concerned with the studies on complexes of 2-Chlorobenzaldehyde, Thiosemicarbazones. By emphasizing this point the objectives of the present work are as follows: synthesis of the 2-Chlorobenzaldehyde thiosemicarbazone (2-[(2-Chlorobenzylidene)]) Hydrazine carbothioamide. The composition of 2-Chlorobenzaldehyde was determined by the spectral analysis. For the characterization of this compound by 1HNMR and IR spectral studies. The complexes of 2-chloro benzaldehyde were characterized by 1HNMR, 13CNMR, IR and UV spectral studies. The 2-Chlorobenzaldehyde thiosemicarbazone, have been screened against Bacteria (a) gram positive Staphylococcus aureus (Saureus), (b) gram negative Ecoli and fungi Aspergillus Niger and Candida albicans by the agar disc diffusion method. Therefore antimicrobial activities are analyzed in this work specifically for 2-Chlorobenzaldehyde thiosemicarbazone crystal. This crystal was grown by solution growth technique and analyzed analytically.