Nanoporous boron nitride (BN) flake was synthesized in large scale at temperatures between 550 and 600 degrees C for 10 h via the simple reaction between NaBH4 and CH5N3S. X-ray diffraction and Fourier transform infrared spectra confirm the formation of hexagonal BN. Examination by high-resolution transmission electron microscope reveals that the product is comprised of nanoporous flake, which exhibits a high surface area of 214 m(2) g(-1) characterized by nitrogen adsorption-desorption isotherms. The nanoporous BN flake has good thermal stability and oxidation resistance up to 800 degrees C measured by thermogravimetric analysis. (C) 2015 Elsevier B.V. All rights reserved.