Sulfuric acid is used as an extraction agent to remove PEO–PPO–PEO templates in the organic–inorganic mesoporous nanocomposites from the triconstituent co-assembly which includes the low-polymerized phenolic resins, TEOS and triblock copolymer F127. The XRD and TEM results show well ordered mesostructure after extraction with sulfuric acid. As followed from the N 2 sorption isotherms the extracted composites possess high surface areas (332–367m 2 /g), large pore volumes (0.66–0.78cm 3 /g), and large pore sizes (about 10.7nm). The FT-IR analysis reveals almost complete elimination of triblock copolymer F127, and the maintenance of organic groups. This method shows potentials in removing templates from nanocomposites containing functional moieties.