摘要： Nanotechnology is a science that deals with various structures of matter at the scale of a billionth of a meter. It is also the study of changing matter at the nanometres scales to create novel structures and devices. A nano particle is the most fundamental unit component in the fabrication of a nanostructure and is far smaller than the world of everyday’s objects that are described by Newton’s laws of motion. But on the other side, a nanoparticle is bigger than atoms or simple molecules that are governed by quantum mechanics. In general, the size of a nano particle is seen in the range 1–100 nm. Nanoparticles have physical and chemical properties that are different from bulk metals like low melting points, high specific surface areas, good optical properties, mechanical strengths and specific magnetizations. No wonder, nanotechnology plays a significant role in electronics, medicine and other fields. Recent growth of zinc oxides (ZnO) as semiconducting materials with novel, unique optical and magnetic properties has made them to be the versatile and suitable materials for electronic, spintronic, optoelectronic, photocatalytic examination along with antibacterial applications. From the above-said applications, the present review paper specifically focuses on finding the right material with excellent optical features for photocatalytic and antibacterial applications.