The hydrogen bonds in four coals with different rank and different sulfur content were checked using the in situ diffuse reflectance FTIR (DRIFT) method. Besides the hydrogen bonds formed by -OH and -COOH groups, there exists a new kind of hydrogen bond (SH-N) formed by the -SH in the thiophenols or mercaptans and the nigrogen in pyridine-like compounds in coal. The absence of this shoulder peak in the IR spectra of low rank coals (even high sulfur) can be attributed to the high content of -COOH groups, and consequently the strong and broad absorbance in carboxylic acid dimers in this range covers the weak absorbance of SH-N. However, when the low rank coals were heated to 620degreesC in Ar atmosphere and the -COOH disappears, the peak of SH-N clearly occurs. To summarize all the work on this new hydrogen bond, we assign it to the position of about 2514 cm(-1).