Mesoporous BN was prepared at 550°C for 10h or so via a simple reaction between NaBH 4 and CO(NH 2 ) 2 . X-ray diffraction demonstrates the formation of t-BN with lattice constants a=2.46 and c=6.67Å. High-resolution transmission electron microscopy displays a lot of porous films in the product, which possesses a high surface area of 219m 2 g −1 and a pore size primarily around 3.8nm tested by nitrogen adsorption–desorption method. The mesoporous BN exhibits a strong luminescence emission around 3.41eV in the cathodoluminescence spectra, a high stability in both morphology and structure, and good oxidation resistance up to 800°C. The byproducts generated during the reaction are responsible for the formation of the mesoporous BN.