Constraint of the growth directions or exposed facets of nano-/microstructures has been long regarded as a popular research topic due to the various anisotropic properties of crystals. We report here, for the first time, not only uniform and phase-pure but also tunable perovskite BiFeO 3 crystallites with different predominantly exposed facets have been successfully synthesized via a facile one-pot hydrothermal approach at 200 °C under the presence of potassium hydroxide and polyethylene glycol. Pills and rods with dominant {111} c facets and cubes with {100} c exposed facets have been obtained by adjusting the alkaline conditions of the precursor solution. Furthermore, due to the distinct dominant facets of BiFeO 3 crystallites, {111} c dominant pills and rods grant a significant enhanced visible light response, suggesting that the designed structures can give rise to better performance in future photovoltaic and photocatalytic applications of BiFeO 3. ; Department of Applied Physics