Excess enthalpies of binary mixtures between each of chlorobenzene, fluorobenzene, bromobenzene, chlorotoluene and fluorotoluene and methyl methylthiomethyl sulfoxide (MMTSO) or dimethyl sulfoxide (DMSO) have been determined at 298.15 K. All mixtures showed positive enthalpy change over the whole range of mole fractions. Partial molar enthalpies of the mixtures containing MMTSO(2) around 0.95 in mole fraction have maxima and minima. Linear relations are obtained between limiting excess partial molar enthalpies and the square of the dipole moment except H-2(E,infinity) of the mixtures containing fluorotoluene.