An anthracene oil with a boiling point of 250-370 degrees C was reacted with sulfur (5-20 wt%) at 250-300 degrees C for 2 h. The extent of anthracene oil conversion to a carbon precursor (pitch-like material) was monitored from the weights of the residues obtained by thermogravimetric analysis at 350 degrees C (R-350), the temperature at which the anthracene oil residue is zero. Anthracene oil readily reacts with sulfur, the initial concentration of sulfur being the main controlling parameter of the reaction. The anthracene oil components showed different reactivities with sulfur, as determined by gas chromatography of the toluene-soluble fraction, and also followed different mechanisms because of their different structures. Studies by probe mass spectrometry of the pure compounds revealed the type of reaction mechanisms involved in the process. The amount of sulfur incorporated into the reaction products determined the optical texture of the resultant cokes.