This work analyses the composition, morphology, and thermal behavior of the carbonaceous materials deposited during the thermal treatment of bio‐oil (thermal pyrolytic lignin—TPL). The bio‐oil was obtained by flash pyrolysis of lignocellulosic biomass (pine sawdust), and the TPLs were obtained in the 400–700 °C range. The TPLs were characterized by performing elemental analysis; 13C NMR, Raman, FTIR, and X‐ray photoelectron spectroscopy; SEM; and temperature‐programmed oxidation analyzed by differential thermogravimetry and differential scanning calorimetry. The results are compared to a commercial lignin (CL). The TPLs have lower oxygen and hydrogen contents and a greater aromaticity and structural order than the CL material. Based on these features, different valorization routes are proposed: the TPL obtained at 500 °C is suitable for use as a fuel, and the TPL obtained at 700 °C has a suitable morphology and composition for use as an adsorbent or catalyst support.