Synthesis of nanomaterials with diverse morphology for different applications in medicine and opto-electronics has become the subject of great interest for the researchers now-a-days. For this, different facile synthesis routes have been developed. But, the search for a reliable, cost effective and reproducible technique which will have the control over size and morphology of the materials has not come to an end. In this context, utilization of ultrasound in synthesizing nanostructured materials is a novel and versatile tool due to easy reaction conditions, formation of purer products and waste minimization. Inorganic metal oxides such as ZnO have attracted a lot of attention over the past decade due to their novel applicability in industry. It's interesting properties such as high conductance, chemical and thermal stability, wide and direct band gap of 3.37 eV and a high excitation binding energy of 60 meV have made it the favorite of researchers to be probed more and more. This book describes the efforts made in synthesizing nano ZnO by sonochemical technique and studying the structural and optical properties.