We have investigated noncovalent interactions of two aromatic compounds (toluene and p-cresol) with Xe atoms by using infrared spectroscopy in a Ne matrix and quantum chemical calculations. The present results show that the methyl group of these molecules is a sensitive probe of the interaction with Xe. We have used the molecules with the deuterated methyl group, possessing a relatively simple spectrum; which allows us to detect characteristic vibrational shifts in the complexes, in which a Xe atOm interacts with the aromatic pi electron system (pi structure). For the p-cresol center dot center dot center dot Xe complex, we also observed evidence of the 1:1 H-bonded structure: The amount of the H-bonded structure of the cresol Xe complex is relatively small; which agrees with the calculated interaction energies (stronger interaction for the pi structure). The bands of the 1:1 complexes of p-cresol and toluene with Xe appear at low Xe concentration and their intensities relative to the monomer bands are nearly proportional to the Xe/Ne concentration ratio. For the p-cresol Xe system, additional OH stretching bands appear at higher Xe concentrations, which are suitable for the complexes with several Xe atoms. The pi structures studied in this work can probably be formed in the aromatic amino acids, for which these simple aromatic compounds are useful models. Case of