"The improvement of fabrication technology over the last decades enables the accurate creation of almost arbitrarily shaped nanoscale metal structures. In such systems, quasi-bound surface modes (plasmons) provide strong, sub-wavelength confinement of electromagnetic fields. This confinement leads to strongly increased coupling between light and matter, and increases the possible spatial resolution to far below the diffraction limit. These properties make plasmonics a quickly growing and multidisciplinary subject, with applications in physics, chemistry, biology and engineering. A particularly relevant topic is the coupling of quantum emitters (such as atoms, molecules, quantum dots, or color centers in diamond) to plasmons. By concentrating light with the use of plasmons, the mismatch between the absorption cross section of the emitter and the size of the light beam can be circumvented. It is then even possible to reach the strong coupling regime, where the elementary excitations become hybrid states with mixed light-matter character. The major aim of StroCOMP is to develop new insights into the strong coupling between plasmons and organic molecule excitations, forming so-called ""plexcitons"". Due to the complex molecular structure, organic molecule plexcitons are still not fully understood. In addition to the system itself, we will study two relevant applications: One is the manipulation of chemical structure and reactions through strong coupling, exploiting the modification of the chemical potential energy surface. The second application is plexciton condensation, driven by their Bose-Einstein statistics. This exploits the possible ultralight effective mass of plexcitons to enable condensation and quantum degeneracy even at room temperature, and in addition to being of fundamental interest could represent a pathway towards a very low-threshold coherent light source."