We report here an electrodeposition route for the preparation of oriented and well-defined ZnO nanostructures by kinetically controlling the growth rates of various facets of the deposit by appropriate capping agents. We demonstrated that adsorption of Cl- takes places preferentially onto the (0001) planes to hinder the crystal growth along the c-axis, and results in the formation of platelet-like crystals. It is also shown that the morphology evolved from hexagonal tapers to hexagonal rods and rhombohedral rods by changing the compositions of the capping agents. Furthermore, strong UV emissions at 380 similar to 390 nm and negligible green bands at around 500 nm were observed, indicating that these ZnO electrodeposits are highly crystallized and of excellent optical quality.