The proposed research is directed towards the synthesis, modification, and study of structure/property relationships of nonlinear optic inclusion materials. Three thrusts are considered: 1) Exploratory synthesis of new nonlinear optic active host framework materials; 2) Nonlinear optic active host systems generated by selectively induced anisotropic stress coupled with compositional driven phase instabilities; and 3) Nonlinear optic nanocomposites synthesized by the self-organization and alignment of hyperpolarizable atomic and molecular entities on the surface and within the channels of polar inorganic molecular sieves. Exploratory synthesis using hydrothermal, flux, solid state, sol gel and thin film techniques are proposed along with the use of guest/host ion exchange, sorption, and solid state substitution chemistry to modify nonlinear optic behavior. A second objective of this research is to examine atomic displacements externally induced by temperature and pressure and their relation to elecro- optic related phase changes. Inclusion guest and host chemistry can be used to control second harmonic generation response over a wide range. The chemistry and characterization needed to better understand this relationship will be studied and theoretically modelled during the proposed funding period and applied to the exploratory synthesis of new nonlinear optic materials.