Two lignites (Mequinenza, Spain) and two subbituminous coals (Teruel, Spain), their demineralized derivatives (HCl/HF+HCl) and their corresponding derived vitrinite concentrates were submitted to hydroliquefaction in tetralin in fixed conditions to study a possible synergism of vitrinite concentrates in the original coal matrix. Sufficiently pure amounts of vitrinite concentrates were isolated by a method based on differential centrifugation in CsCl. The coals were characterized by densimetric and petrographic analyses including reflectance-frequency distributions. A synergism for vitrinite concentrates related to the demineralized coals has not been found here because all the vitrinite concentrates, once separated, have similar or higher reactivity than in the corresponding original coal matrix. On the other hand, the studied lignite-derived vitrinite concentrates have proved to be much more reactive than the subbituminous-derived ones. Displacements of Absorbance-Density curves and maxima toward higher densities (densimetric analyses data) and appearance of V-4 vitrinite type structures (coal reflectograms) in the case of the subbituminous coals imply differences in chemical structures for the lignite and the subbituminous derived vitrinite concentrates which could explain the differences in reactivity.