This study describes an accurate partition function obtained evaluating the configurational integral of molecular solutes with a computationally feasible method. The key features of this method include the partition function's factors for translation (calculated according to the approach of the Lennard-Jones-Devonshire theory of liquids) and libration. The proposed molecular partition function has been successfully tested computing entropies of vaporization and molar heat capacities at constant volume for the four common liquids dichloromethane, acetonitrile, methanol, and water. The formulation of pressure-dependent properties is also given through a virial equation, and the evaluation of its simplest term allows the estimate of enthalpies of vaporization. Structural parameters needed by the theory, such as binding energies of particles to the bulk, have been obtained through density functional theory calculations on monomers, dimers, and clusters of the four test liquids.