Carbonaceous materials are highly porous, therefore their properties depend on both pore structure and properties of wall which contains inert maceral-derived component (IMDC) and reactive maceral-derived component (RMDC). Upon heating in metallurgical processes, significant changes can be expected in wall properties of carbonaceous materials as a result of graphitisation. This paper examines the effect of annealing at 700-1500 °C on the microstructures of carbonaceous materials using XRD and Raman spectroscopy. The carbonaceous materials examined in this study included metallurgical cokes, chars and coals. The coal samples were processed at 700 °C in argon atmosphere to remove volatile matter to obtain laboratory char samples. Then coke and char samples were further annealed in a graphite furnace in argon atmosphere for 2 hours at 700, 900, 1100, 1300 and 1500 °C.