ZnO nanocrystals with various morphologies such as nanorod arrays, flower like assemblies, spherical particles, hexagonal cones, and self assembled microstructures were prepared by a solvothermal approach. It was observed that morphology of the ZnO nanostructures were very much solvent dependent in solvothermal approach. Water, ethylenediamine, and ethylene glycol-water mixture favors the formation of nanorods. Flower like assemblies of ZnO were produced in benzene. Spherical as well as cone like nanoparticles and their assemblies were produced in ethylene glycol. The ZnO nanostructures were characterized by X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence studies.