Lignite, anthracite, humic acid fraction of lignite, and their laboratory-prepared black carbon (BC) were characterized in detail by advanced solid state C-13 NMR spectroscopy to examine how the differences in chemical structures of fuels (lignite and anthracite) would affect the structures of their BC. Anthracite was almost completely dominated by aromatics (96.9%), with very minor CCH3. Although lignite contained mostly aromatics (76.1%), significant aliphatics (21.3%) as well as small amounts of COO/N-C=O and O-alkyls were also present. In addition, anthracite had more aromatic C-C groups than lignite. Their BC samples both exhibited increased oxygenated functional groups such as COO, aromatic C-O and O-alkyl groups, and concomitant decrease of aromatic C-H and nonpolar alkyls. The H-1-C-13 recoupled long-range dipolar dephasing experiments indicated the growth of aromatic cluster sizes in BC. Although the aromaticity of anthracite was much larger than those of lignite and lignite humic acid, their aromatic cluster sizes were quite similar. The BC samples had much larger aromatic cluster sizes than anthracite despite their smaller aromaticities. Therefore, higher rank or higher aromaticity may not imply larger aromatic cluster size in coal. The structures of two BC samples were similar despite the contrasting structural differences of their original coals. (C) 2011 Elsevier B.V. All rights reserved.