Layered and hexagonal mesostructures of nickel-aluminum oxides templated by alkyl sulfate assemblies were synthesized for the first time by the homogeneous precipitation method using urea. X-ray diffraction patterns and transmission electron microscopy (TEM) proved that there was a transformation from layered to hexagonal mesostructure within a prolonged time of 20 h. The Brunauer-Eminett-Teller surface area was reported after solvent extraction and calcinations at a large range of temperatures. The mesostructurred hexagonal solid by the anion-exchange with acetate species results in a mesoporous material with a specific surface area of as large as 277 in 2 g(-1). The specific surface area decreased from 299 to 71 m(2) g(-1) as the temperatures of calcination increasing from 523 to 1033 K. (c) 2007 Elsevier B.V. All rights reserved.