Micro-sized ZnO crystals with different shapes have been successfully synthesized by a simple solvothermal reaction of zinc nitrate hexahydrate and julolidine in N, N-dimethylformamide (DMF). The growth of ZnO crystals with tunable shape was controlled through a suppressed crystal growth of the (0 0 0 1) facets along c-axis direction due to the julolidine compound selective adsorbing on the positive (0 0 0 1) facets by coordinating Zn cations with its N atoms. Systematic reactions in the presence of different amounts of DMF were conducted to control the formation of various well-shaped ZnO crystals. The selective adsorption of julolidine on the growing facets resulted in the formation of grooved hexagonal disks, hexagonal disks, hexagonal pyramids, and hexagonal rods. (C) 2010 Elsevier B.V. All rights reserved.