We reported the chemical synthesis of cross-linked polyaniline (PANI) by a novel solvothermal metathesis reaction of p-dichlorobenzene (C6H4Cl2) with sodium amide (NaNH2) in benzene at 220 degrees C. In this method, the aniline monomer and complicated treatment were needless and the yield of final products was over 50%. The as-synthesized brown samples were NMP-soluble but water-insoluble; and they were characterized by XRD, FT-IR, UV-vis absorption, XPS, elemental analysis, TGA, and TEM. It was found that solvents have significant influence on the final product. The predominant mechanism of chain growth in PANI polymerizations was proposed as the ionic SNAr process; however, further theoretical and experimental investigations are needed to obtain the undoubted evidences. We believe that this novel solvothermal metathesis reaction will give us a new guideline for the synthesis of some polymers. (c) 2005 Elsevier Ltd. All rights reserved.