The book provides an account of preparation of new organic nonlinear optical materials belonging to the chalcone family, characterization of grown crystals by X-ray diffraction, thermal, mechanical and spectral techniques, experimental methods for determining microscopic and macroscopic optical properties to establish a firm relationship between nonlinear optical property and molecular structure of the materials. The book addresses our understanding of the nonlinear polarization mechanism and their relation to the structural characteristics of the materials and development of materials...