Mechanisms dominating pyrolytic processes in coal were investigated by pyrolyzing a well-characterized liquefaction extract; this is likely to contain the metaplastic tar-precursor phase formed during pyrolysis of most coal mass soluble in liquefaction. Experiments were carried out in a wire-mesh pyrolysis reactor at two heating rates (1 and 1000 K s(-1)) at 500 and 700 degrees C. Molecular mass distributions of the extract and of the tars produced from it were compared by size exclusion chromatography (SEC) with UV and evaporative analyzers in series. Structural comparisons were carried out by planar chromatography and FT-IR spectroscopy. Our findings may be summarized as follows : (i) The original (Point of Ayr) coal sample was pyrolyzed for comparison, Tar yields from the dried extract were considerably greater than those from the coal : tetralin-derived products in the dried extract contributed to this result. (ii) A significant shift to smaller molecular masses was observed when the dried extract was pyrolyzed. (iii) The fraction of lighter material in the pyrolyzing substrate with MMs comparable to those of evolved tars was sufficient to make up the whole of the tar product; we cannot, however, distinguish between direct distillation of light components and cracking of large MM material as the origin of material ending up in the tar. (iv) The presence of tetralin derivatives in the dried extract and its tars indicates that the distillation of light components from the extract is possible, (v) Comparison of product distributions from untreated coal and dried extract, obtained during slow (1 K s(-1)) and rapid (1000 K s(-1)) pyrolysis, provides support for the view that recombination reactions may be responsible for the loss of tar during slow heating compared to fast heating. (vi) The tars were more aliphatic and contained fewer aromatic substituents than the extract itself. Tar release and capture took place under conditions minimizing extraparticle secondary reactions and this work pinpoints the progress of particular reactions taking place in the metaplast prior to tar release, (vii) Planar chromatography showed the dried extract and its tars to consist of strongly polar mixtures.