For many single-molecule applications it is mandatory to immobilize the molecules under investigation. The most common techniques use non-fluorescent plastics, i.e. host-matrices, in which the sample molecules are embedded at highly dilute concentrations. In most studies the position and orientation inside the matrix are neglected, although they have a strong impact on its fluorescence properties. For example, the collection efficiency and fluorescence lifetime is altered, if the molecule is close to the plastic-air interface. Additionally, the orientation will directly impact the absorption and emission polarization. Both effects will mask important spectroscopic observables, which could otherwise be used to derive proper structure-function relationships for complex molecules. An additional sample preparation step, based on solvent vapor annealing [A] was applied to influence positon and orientation of molecules within the host matrix. Having the possibility to influence these parameters allows to account for special requirements in organic electronics, such as increased out-coupling efficiency of OLEDs and electrical connectivity of the molecules. Single molecule spectroscopy was used to determine the position and orientation of molecules utilizing a monodisperse ring-shaped model system with a high triplet yield. The triplet state can be easily depopulated under ambient conditions for molecules close to the surface, but remains partly unquenched inside the film. Therefore, the meta-stable triplet state quenches the photoluminescence of molecules deep inside the film, making the intensity available as an observable for the spatial distribution of the molecules inside the film. The ring-shaped structure of the molecule [B-D] together with excitation polarization spectroscopy reveals the orientation of the molecule with respect to the sample plane. In excitation polarization spectroscopy the photoluminescence intensity is recorded while rotating the polarization of the excitation source. A low modulation in intensity points towards a molecule oriented flat with respect to the sample plane whereas a high modulation means that it is oriented perpendicularly to the sample plane. Solvent vapor annealing enables diffusion of the molecules and allows the molecules to reach thermodynamic equilibrium within the matrix. This is achieved by placing the sample in a flow chamber and applying a small constant flow of solvent saturated nitrogen. The solvent percolates the film and lowers the glass transition temperature below ambient conditions. After a certain time the chamber is purged with pure nitrogen until the solvent is evaporated and the molecules are fixated again. We found that after this additional treatment of the plastic film, all molecules are oriented parallel to the surface and are in close proximity to the plastic/air interface. [A] Vogelsang et al., Nature Mater. 10, 942-946 (2011) [B] Aggarwal et al., Nature Chem. 5, 964 (2013) [C] Mössinger et al., J. Am. Chem. Soc. 132, 1410 (2010) [D] May et al., J. Am. Chem. Soc. 136, 16732–16735 (2014)