Solution-based synthesis is a powerful approach for creating nano-structured materials. Although there have been significant recent successes in its application to fabricating nano materials, the general principles that control solution synthesis are not well understood. The purpose of this LDRD project was o develop the scientific principles required to design and build unique nanostructures in crystalline oxides and II/IV semiconductors using solution-based molecular self-assembly techniques. The ability to synthesize these materials in a range of different nano-architectures (from controlled morphology nano crystals to surface templated 3-D structures) has provided the foundation for new opportunities in such areas as interactive interfaces for optics, electronics, and sensors. The homogenous precipitation of ZnO in aqueous solutions was used primarily as the model system for the project. We developed a low temperature, aqueous solution synthesis roue for preparation of large arrays of oriented ZnO nano structures. Through control of heterogeneous nucleation and growth, methods to predicatively alter the ZnO micro structures by tailoring the surface chemistry of the crystals were established. Molecular mechanics simulations, involving single point energy calculations and full geometry optimizations, were developed to assist in selecting appropriate chemical systems and understanding physical adsorption and ultimately growth mechanisms in the design of oxide nano arrays. The versatility of peptide chemistry in controlling the formation of cadmium sulfide nano particles and zinc oxide/cadmium sulfide hetero structures was also demonstrated.