The influence of a hydrotrope, sodium xylenesulfonate (SXS), was determined on the areas of oil-in-water (O/W) microemulsions of water, sodium dodecyl sulfate (SDS), pentanol (C5OH), and aliphatic hydrocarbons. The addition of a hydrotrope extended the microemulsion toward higher hydrocarbon content for the aliphatic hydrocarbons hexane and decane, while the improvement for a typical white oil was less pronounced. The regions are reported in the form of three-dimensional diagrams with five components and provide a rational explanation of the coupling action of a hydrotrope molecule.