Abstract The generation of C 11+-aromatic hydrocarbons has been investigated in a total of thirteen coal samples with mean random vitrinite reflectance ( R r) between 0.45 and 1.00% mainly derived from the Lower Cretaceous German Wealden formation in the Lower Saxony Basin. Yields of total aromatics and selected dicyclic and tricyclic aromatic molecules which were extractable before and after heat treatment of the samples at 350 and 400°C have been determined by medium and high pressure liquid chromatography followed by capillary gas chromatography. Regular variations with increasing R r in the carbon-normalized yields demonstrated that aromatic hydrocarbon generation was strongly controlled by rank. In contrast, variations in maceral composition appeared to be of minor importance. Based on the conceptual model of “open” and “closed” poers, discrepancies in the quantitative distributions of extractable aromatics among unheated and heated coals were attributed to a restricted mobility of molecules contained in “closed” pores, which were accessible to solvent extraction only after the rigid physical coal structure had partially been disintegrated by heat treatment at 350°C.