This book has been written for the students who are doing Ph.D in various University, University colleges throughout the world. It describes the synthesis, characterization and applications of NLO materials for optoelectronic devices. This book contains 4 chapters, which gives the introduction and growth mechanisms in the lucid and simple way to make the students follow the procedure very easily . Our work is mainly oriented to synthesis as to evaluate the structural, topographical and physical properties of Cesium sulfamate, Cesium Tartrate, and N'-[(E)-(4-Bromophenyl)(phenyl)methylidene]-4-methyl benzene sulfono hydrazide, were grown by slow evaporation technique. The grown crystals were characterized by various characterization techniques such as single crystal XRD, FTIR, dielectric, TG/DTA, microhardness and Z-scan studies. Single crystal X-ray ,etc.,