Supported liquid-phase catalysts offer one possibility for the heterogenization of a homogeneously catalyzed reaction system. It is shown that their activity as well as their stability are mainly influenced by the form of the liquid distribution in the pore space of the support used to prepare the contacts. While the liquid, for low liquid loadings, is distributed in the pore space as a thin film, it blocks the pore space for higher q-values. The complexes embedded in the film are too immobile to develop their activity. The blocking process, on the other side, reduces the accessibility of the complexes in the solution by the educt gas molecules, which leads to low activity values, as well. Thus, optimal values are obtained for middle q-values. Since the stability of SLP catalysts mainly depends on the amount of liquid lost by evaporation processes, the liquid distribution in the pore space influences this property as well, because it determines the mean curvature of the liquid surface and, therefore, the vapour pressure.