Bi2WO6 uniform hierarchical nest-like structures have been successfully synthesized through an ionic liquid-assisted hydrothermal method in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4). The Bi2WO6 hierarchical structures have an average diameter of about 3-5 mu m and are assembled by Bi2WO6 nanosheets with size ranging from 16 to 20 nm. The results show that ionic liquid [Bmim]BF4 is vital for the formation of Bi2WO6 nest-like hierarchical structures. The UV-vis diffuse reflectance spectroscopy indicate that Bi2WO6 hierarchical nest-like structures induce a significantly enhanced optical absorbance in the UV-vis region, which is ascribed to multiple scattering within the hierarchical assemblies to the lengthened optical path length for light transporting. (C) 2010 Elsevier B.V. All rights reserved.