Raw coal, HCl-treated coal, and HCl-HF treated coal samples ZnCl2, NiCl2, CoCl2, CuCl2, and Fe2O3. SO4 as catalysts were pyrolyzed under various temperature and time conditions in an inert atmosphere. The conversion of organic matter was calculated. The change in the aliphatic hydrogen and the degree of aromatic condensation by FTIR technique have been examined a function of temperature, time, and catalyst type. The volumetric swelling ratio of the chars obtained in different experimental conditions have been measured using the pyridine swelling technique, and the extent of cross-linking in the macromolecular network of chars was examined. It was found that the cross-linking increased with the catalysts.