Hollow, urchin-like carbon spheres with electromagnetic function were prepared by a carbonization process at 1200 °C under an argon atmosphere by using template-free-synthesized, urchin-like, hollow spheres of polyaniline containing FeCl₃ as the precursors. The resulting hollow, urchin-like carbon spheres not only have a high conductivity at room temperature (≈12.3 S cm^–1), but they also exhibit ferromagnetic properties. The high conductivity at room temperature results from the graphite-like structure, whereas α-Fe or γ-Fe₂O₃ nanoparticles produced by FeCl₃ during the carbonization at 1200 °C are attributed to the ferromagnetic properties. Interestingly, the electromagnetic functional hollowurchin-like carbon spheres could be used as a reversible dye adsorbent. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)