A soluble fraction of coal tar pitch (CP) in tetrahydrofuran (THF) was reacted with p-benzoquinone (BQ) at 160 and 180 degrees C and followed by carbonization and graphitization. The reaction and carbonization behavior were monitored in-situ by using differential scanning calorimeter, high-temperature H-1 NMR and high-temperature ESR. The reactions of CP and BQ resulted in an increase in molecular weight with an increase in BQ concentration. Such molecular weight increases led to the formation of a less ordered structure due to the reduced mobility of the molecules. The relative order of the carbonized materials was determined by using polarized light microscope and X-ray diffraction. The molecular size of the precursor was recognized as an important factor in determining the morphology of carbon materials.