Abstract To assess the suitability of transmission electron microscopy (TEM) for investigating the detailed process of coal/solvent interaction, TEM observations have been made of small blocks of Liddell vitrinite that had been treated with tetralin in an autoclave at 320 and 350 °C. In vitrinite treated at 320 °C cell cavity fillings became porous, while the walls between cell cavities remained uniform and showed no internal texture. In vitrinite particles treated with tetralin at 350 °C two zones were recognizable at the edges of the particles: a more electron-dense inner zone and a less electron-dense outer zone. Also present in these specimens were plastospheres consisting of two different materials, primary vitroplast (a more electron-dense core) and secondary vitroplast (a less electron-dense crust). Such detailed texture has not been observed with incident light microscopy, and TEM techniques provide useful information not previously obtainable.