A broad range of fatty acids as well as fatty-acid-based, long-chain compounds are synthesized on the basis of triglycerides, which are mainly found in natural fats and oils. These long-chain compounds comprise, for instance, fatty-acid methyl and ethyl esters and fatty aldehydes. Saturated representatives of these individual families are composed of an identical head domain which is connected to an n-alkylic residue that only varies in chain length within a homologous series. In this work, this fact was taken into account for modeling of thermodynamic properties using a heterosegmental approach of the Perturbed Chain Statistical Associating Fluid Theory. For this purpose, the n-alkylic residue within a homologous series was modeled using the pure-component parameters of n-alkanes, whereas the parameters for each identical head domain were universally determined. With this heterosegmental approach, polar interactions among the identical head domains were explicitly taken into account. Due to its group-contribution-like character, the heterosegmental approach enables the prediction of thermodynamic properties of other compounds within a homologous series. Applying the new approach, vapor pressures and liquid densities of the pure long-chain compounds could be represented in very good agreement with the available experimental data. Furthermore, the interactions between the n-alkylic residue and water can be described using independent solubility data of the binary n-alkane + water mixtures. Excess enthalpies and excess volumes of the binary long-chain compound + n-alkane mixtures as well as mutual solubilities in the binary methyl alkanoate + water mixtures were predicted to be in remarkable agreement with the available experimental data for a broad range of chain lengths.