With the advancement of cavity quantum electrodynamics and its recent application to molecules, using the quantum properties of light to control photo-chemistry has come into reach. Recent, ground breaking experiments have show that one can utilize the vacuum field of an optical nano-resonator to significantly modify the potential energy landscape and thus its photo-chemistry. The underlying effect is the formation of so called “dressed states”, which are created when the quantized radiation field mode couples to a molecular electronic transition. In the resulting coupled light-matter system the molecular and the photonic degrees of freedom are heavily mixed. While this effect is well understood for atomic samples, it is not yet fully understood for molecules. The introduction of the nuclear degrees of freedom requires new theoretical frameworks. This effect can be used to modify reaction pathways of chemical and photo-chemical reactions. This opens a wide range of possibilities to engineer novel types of light driven catalysts. We are looking at the underlying mechanisms and are working on building a suitable tool chest for numerical simulations. With the new insight and tools we want to propose new photo-chemical applications.