"Soot-like" materials, extractable by 1-methyl-2-pyrrolidinone (NMP), have been found in cokes from the lower temperature regions of a blast furnace. Size-exclusion chromatography (SEC) suggests that apparent molecular masses of these materials are very large. An attempt to gain an understanding of the formation mechanism of these "soot-like" materials has been made by means of tracing the changes in the molecular-mass distribution and molecular structure of the NMP-extractable materials from an injectant coal as well as its partially gasified chars and its pyrolytic tars. Variations in the SEC chromatograms provide clues about changes in the apparent molecular-mass distributions of these NMP extracts. Results suggest that the build-up of "soot-like" materials follows from the secondary reactions of tars evolved from the injectant coal. The likely secondary-reaction pathways have been probed by collating structural information on these NMP extracts. The time-resolved 13-16 and 22-25 min elution fractions from the SEC column have been characterized using UV fluorescence (UV F) spectroscopy. Greater concentrations of larger aromatic ring systems are found present in samples formed under conditions appearing more prone for soot formation. The 11-16 min (large apparent molecular mass) effluent from SEC has been examined by Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). Results from FTIR spectroscopy are consistent with the UV F data, showing more significant extents of dehydrogenation under conditions more prone to form soot. Similarly, TEM results show that larger amount of graphene layers exist in samples exposed to more soot-prone conditions. The emerging picture for the formation of "soot-like" materials involves a well-defined sequence. Tars evolved from the injectant coal undergo secondary dehydrogenation, condensation, and reploymerization reactions, which eventually lead to the formation of the NMP-extractable "soot-like" materials of large apparent molecular mass.