Herein, we present a model system that allows the investigation of a directed intramolecular singlet oxygen (O-1(2)) transfer. Furthermore, we show the influence of singlet oxygen lifetime and diffusion coefficient (D) on the preference of the intramolecular reaction over the intermolecular one in competition experiments. Finally, we demonstrate the distance dependence in quenching experiments, which enables us to draw conclusions about the role of singlet oxygen and O-1(2) carriers in photodynamic therapy.