Abstarct: In this Thesis Europium and Dysprosium doped ZnO nanostructures were synthesized by chemical vapor deposition and hydrothermal methods. Effects of Al, Cu and Mg doping, morphology and annealing in different ambient on structural and optical properties of ZnO nanostructures were investigated using X–ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis (PSA), thermo gravimetric analysis (TGA), differential thermal analysis (DTA), differential thermo gravimetry (DTG), diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). This study recommends that both of intrinsic and extrinsic defects facilitate energy transfer (ET) from the ZnO host to La3+ ions and consequently have efficient role on producing intense lanthanides emission at indirect excitation. The results also showed that annealing process improved the crystal structure of ZnO nanostructures due to decrease of surface defects; however decreased energy transfer and lanthanid emission because of diminishing in defects. In addition in ZnO nanorods sample with more surface area in comparison with ZnO nanosheets and microstructure samples, deep level emissions are enhanced.