The acylation of o-cresol with pyromellitic dianhydride (PMDA) has been experimentally studied. The optimum conditions of the acylation reaction of o-cresol with PMDA have been determined. The synthesis has been performed in o-cresol melt at 120 degrees C for 30 h at a reactant molar ratio of PMDA : o-cresol : SnCl4 = 1.0 : 4.1 : 2.0. The yield of 3,3,7,7-tetrakis(3-methyl-4-oxyphenyl)pyromellitide is 62.0% of the theoretical value. The structure of the target synthesis product has been proven by instrumental methods, namely, elemental analysis; thin layer chromatography (TLC); UV, IR, and H-1 NMR spectroscopy; DSC; and high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS). The revealed properties of 3,3,7,7-tetrakis(3-methyl-4-oxyphenyl)pyromellitide allow it to be recommended as a tracer for oil reservoir evaluation.