**Abstract**

Pyrolysis techniques use thermal energy to degrade large molecules into smaller and volatile molecules, which can be analyzed by gas chromatography to determine the composition or structure of the initial sample. A laser system coupled to a GC/MSMS, for analysis of these species, gave rise to the technique called Laser MicroPyrolysis-GC/ MSMS (LmPy-GC/MSMS). The laser micropyrolyzer is a hyphenated system with a laser source, an optical microscope, and a GC/MSMS technique. In this hyphenated technique, a collimated, short-duration laser beam with a large amount of energy can be focused on isolated components, or a macromolecule inside a heterogeneous matrix, promoting the thermal cleavage and producing smaller components, which are finally analyzed and characterized by GC/MSMS. The LmPy-GC/MSMS has been proven to be able to supply important molecular data on organic fossils, coals, source rocks, etc., improving the knowledge and the understanding of the compositions and opening a horizon in the study of several heterogeneous materials.

**Keywords:** laser micropyrolysis, organic matter, instrumental development, gas chromatography, mass spectrometry
