Poly(o-phenylenediamine) (POPD)-derived functional carbon materials with excellent capacitive performance (see figure) are successfully synthesized by means of an integrated one-step process, in which FeCl3 not only oxidizes the polymerization of the organic monomers but also activates the carbonization. Furthermore, extensive research has proved that this strategy to discover novel carbons is useful not only for capacitors but also for other energy storage/conversion devices.