The potential of Cl doping for tuning the structural and optical properties of ZnO nanostructures has been examined. The Cl concentration in the ZnO structure was evaluated using EDAX analysis. SEM micrographs illustrated that morphology of ZnO changes from nanorods to nanodisks and finally to nanoflakes with increase in doping level. The XRD analysis also confirmed reduction in vertical growth of ZnO, showing suppression of (002) peak with Cl doping. Photoluminescence studies revealed that substitutional doping of Cl suppresses the green emission by occupying O sites and promotes blue emission by inducing Zn vacancies in the lattice structure. (C) 2016 Elsevier B.V. All rights reserved.