A study of nonvolatile bituminous residues and coal materials by pyrolysis gas chromatography has been undertaken. The objective is to determine the coal and the coke precursors in a residue from the coprocessing of coal and bitumen. This was investigated by quantifying eight model aromatic compounds and their coeluting compound groups in the pyrolysis products. Five samples consisting of Cold Lake coke, nonvolatile bituminous residue obtained from coprocessing Forestburg coal with Cold Lake bitumen, Forestburg coal, and a residual coal from liquefaction were pyrolyzed from ambient temperature to 900°C, and the volatile products were analyzed by gas chromatography. Hydrocarbons up to C7have been detected in the gas region of the pyrogram, methane being predominant. The wide variety of polynuclear aromatic hydrocarbons produced by pyrolysis of these samples arise from the cleavage of their highly condensed aromatic structures. Naphthalene, phenanthrene, and pyrene were abundant in the Cold Lake coke. On the other hand, indole and fluoranthene predominate in the Forestburg coal. Residual coal resembles Forestburg coal more than other nonvolatile residues.