Abstract: Infrared spectroscopy affords a useful method for the determination of the orientation of molecules sorbed on layer silicates. The orientation of the molecules can be inferred from the observed dichroism of specific absorption bands. Examples of the analysis are illustrated in three complexes with pyridine. One flat and one vertical orientation are observed for the ionic form dependent on layer charge. A different vertical orientation is observed for the neutral molecule. The interpretation of the infrared absorption analysis is confirmed by X-ray diffraction.