In the footsteps of Liebig and Berzelius: A material first synthesized in 1834, carbon nitride (C3N4), was synthesized in a graphitic mesoporous form by using silica nanoparticles as templates. The resulting electron-rich solid is an active catalyst for the Friedel–Crafts acylation of benzene with hexanoyl chloride. Presumably the catalysis arises from a shift of electron density from the MOs of the catalyst to the unoccupied orbitals of benzene (see picture). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z600412_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.