Hexamethylbenzene (HMB) is a methyl benzene derivative. Its overtone spectra in carbon tetrachloride solution shows doublet structure due to two types of configurationally inequivalent hydrogens. The heat of solution of crystalline HMB has been obtained at 25°C from which the heat of fusion has been deduced by extrapolation process. The internal motion of the methyl groups has been explained by empirical force field calculations. Polarized Raman spectra of HMB at room temperature have been analyzed.