Mesogenic and mesophase pitches were produced from Ashland A 240 pitch in a stirred tank reactor under various pyrolysis conditions. Isothermal experiments showed strongly different properties of the products as compared to results with an earlier lot of the same pitch. The products were characterized by their solubility in tetrahydrofuran and N-methyl-pyrrolidone, their mesophase content, glass transition temperature, coke yield, and aromaticity. Pitch reactivities with oxygen in view of a stabilization treatment were analyzed by FT-IR. Copyright (C) 1996 Elsevier Science Ltd