The thiosemicarbazone of 4-Chlorobenzaldehyde and Thiosemicarbazone of M-Nitrobenzaldehyde is an interesting of organic compound in the crystalline nature. The quartz meth glass which is grown slow evaporation method from the solvent methanol. The harvested crystals were purified by repeated recrystallization. FT-IR spectroscopic study was held out on the growth, recognize the fundamental function group. Optical absorption studied illustrate the low absorption in the entire UV and visible spectral. The UV-Visible Spectra are confirming the optical transparency. This is more helpful to use these crystals in option applications. The harvested crystals Thiosemicarbazone of 4-Chlorobenzaldehyde and Thiosemicarbazone of M-Nitrobenzaldehyde were characterized by proton nuclear magnetic resonance and of 13C NMR spectra which show the molecular structure of the crystals. Its thermal stability for analysis in the crystal by TGA and DSC. The TGA and DSC confirm the decay of the sample at 210°C. It further confirms the grown crystal Thiosemicarbazone of 4-Chlorobenzaldehyde and Thiosemicarbazone M-Nitrobenzaldehyde is thermally stable up to 210°C. The frequencies was identified in the crystal by dielectric properties. The second harmonic generation efficiency of the powdered thiosemicarbazone of 4-Chlorobenzaldehyde and Thiosemicarbazone of M-Nitrobenzaldehyde and was tested using Nd: YAG laser and it is found to be 6.1 and 5.6 times higher than that of urea.