Using a combination of instrumental and chemical methods many new classes of compounds appearing as homologous series have been detected in Athabasca oil sand bitumen and in the chemical and thermal degradative products of asphaltene and the heavy ends of maltene. In general, the volatile portion of the maltene is rich in cyclic terpenoid structures and devoid in aliphatic compounds ornormalalkane-derived cyclic molecules while the asphaltene fraction and heavy ends of maltene are abundant innormalalkyl-substituted aromatics, thianes, thiolanes, thiophenes, benzo- and dibenzothiophenes