Measurements of the energies of combustion are reported for 2-methylbiphenyl (Chemical Abstracts registry number [643-58-3]), and diphenylmethane (registry number [101-81-5]). Standard enthalpies of combustion and formation in the condensed state are derived for both compounds. Standard enthalpies of vaporization at 298.15 K are reported for both compounds and the corresponding ideal-gas standard enthalpies of formation derived. The results are compared with literature values and discrepancies arising from the use of values for diphenylmethane from a comprehensive compilation are clarified.