Different ZnO nanostructures are attributed to different electronic properties which are favourable in the application of photocatalysis, sensing and energy harvesting. The non toxic behaviour of ZnO nanostructures lead to the use of this material in environmental sensing and environmental remediation. In ZnO Nanostructures: Advances in Research and Applications, a large-scale synthesis of undoped low-dimensional semiconductor metal oxide nanostructures is performed by simple wet-chemical method using reducing agents at low temperature. The detailed structural, compositional, and optical characterizations of the ZnO nanoparticles were evaluated by powder X-ray diffraction pattern, Fourier-transform infra-red spectroscopy, X-ray photoelectron spectroscopy, electron dispersion spectroscopy and UV-vis. Spectroscopy. Following this, the authors describe the structure electrochemical sensors, listing scientific papers focusing on the detection of different pathogens and analytes, as well as reporting and comparing the performance of the sensors prepared by various groups around the world. The concluding chapter deals with synthesis protocols of ZnO heterostructures along with their role in optoelectronic applications. Their thermodynamic stability and correlation among morphology, defects, and heterostructure with luminating and catalytic properties is also described.