Gel method is promising techniques for growing single crystals of substances which are sparingly soluble in water and decompose before their melting point. In gel method, the rate of diffusion of reactants could be controlled, since the gels are network of cavities of several tens to several thousand of angstroms in diameter, communicating through slightly smaller orifices. Non-linear optical (NLO) materials exhibiting second harmonic generation have been in great demand due to technological importance in the fields of optical communication. Most of the organic NLO crystals usually have poor mechanical and thermal properties and are susceptible for damage during processing though they have large NLO efficiency. Purely inorganic NLO materials have excellent mechanical and thermal properties. Therefore, it is decided to grow and study cobalt iodate and cobalt tartrate crystals by gel method, which possess shorter cutoff wavelength, good optical quality, sufficient nonlinear coefficient, transparency in the UV region, and excellent thermal stability and are characterized by using XRD, FT-IR,TGA/DTA, EDAX, SEM, Electrical Conductivity, Photoluminescence and UV-VIS Spectroscopy.