In order to evaluate the existence of general trends in pyrolysis products with maturation, three series of coals and three series of kerogens (type II-S and type III) of varying maturity were characterized by programmed open-system pyrolysis in a TG-FTIR (thermogravimetric analysis with Fourier transform infrared spectroscopy) apparatus. These series were chosen according to their degree of homogeneity of the precursors, the availability of good estimates of the thermal history, and extensive characterization data of the samples. For most series, similar gas and tar evolution trends during open-system pyrolysis were observed as a function of sample maturity. When increasing maturity, (1) the yields of pyrolytic CO2, H2O and CO decrease, (2) the yields of CH4 and tars go through a maximum, (3) the evolution rates of the oxygenated gases are lower in the whole pyrolysis temperature range, suggesting that during maturation all precursors are removed, regardless of their temperature of stability during pyrolysis, (4) the temperature for the maximum tar evolution presents a systematic shift to higher temperatures, consistent with Rock-Eval T-max, and (5) in several series, the temperature for maximum CH4( )evolution shows a shift toward higher temperatures. The yields of tar and CH4 were found to be series-dependent, while the oxygenated gas yields, for all series including the type II-S kerogens, were found to be very similar for comparable levels of maturation and may represent a series-independent criteria for maturity. This feature may be useful in estimating maturity in type II or II-S kerogens, when vitrinite reflectance measurements cannot be used. This study also confirms previous results that the tar amount can be used to estimate kerogen type, as type II (and type II-S) kerogens produce more tar. In conclusion, the pyrolysis volatile trends observed in the series investigated suggest that the same processes may be involved during the maturation of organic matter. TG-FTIR analysis provides multiple information which can be used for maturity estimation and kerogen type identification. The availability of multiple parameters may lift possible uncertainties in these estimations.