The effect of some white-rot fungi on the bio-liquefaction/solubilization of two low-rank Turkish coals and the chemical composition of the liquid products and the microbial mechanisms of coal conversion were investigated. Turkish Elbistan and Beypazari lignites were used in this study. The white-rot fungi received from various laboratories used in the bio-liquefaction/solubilization of the lignites were Pleurotus sajor-caju, Pleurotus sapidus, Pleurotus florida, Pleurotus ostreatus, Phanerochaete chrysosporium, and Coriolus versicolor. FT-IR spectra of raw and treated coal samples were measured, and bio-liquefied/solubilized coal samples were investigated by FT-IR and LC-MS techniques. The Coriolus versicolor fungus was determined to be most effective in bio-liquefying/solubilizing nitric acid-treated Elbistan lignite. In contrast, raw and nitric acid-treated Beypazari lignite seemed to be unaffected by the action of any kind of white-rot fungi. The liquid chromatogram of the water-soluble bio-liquefied/solubilized product contained four major peaks. Corresponding mass spectra of each peak indicated the presence of very complicated structures.