Single-photon sources are quantum light sources that, when triggered, emit deterministically a single photon and are therefore highly desired in many applications such as quantum imaging, sensing and in information processing. Hence, single photon sources have been an ongoing subject to research for many decades and nowadays even a few start-up companies offer single photon sources. However, for many applications on-demand single photon emission is not sufficient, but deterministic N-photon sources are required that emit exactly N photons with N≥2. These novel N-photon sources do not exist yet but have a broad range of applications, including applications in quantum metrology and lithography, the production of NOON-states for quantum information processing, superresolution microscopy and even medical imaging applications. In the action “DEMONS” we will realize a high-fidelity N-photon quantum light source at the Max Planck Institute for the Science of Light (MPL). More precisely, we will utilize light–matter interactions between molecules and an open scannable and tuneable microcavity at cryogenic temperature to create exotic quantum states that will emit multiphoton quantum light. To do so, we will start with the Fabry-Pérot open microcavity developed at MPL and improve its design for the purpose of this action. Afterwards, we will examine two complementary approaches to create a N-photon quantum light source: In the first approach we will use cooperative coupling of N emitters via the common light field of the microcavity, whereas in the second approach, we will exploit the nonlinearity of the strongly coupled single molecule-microcavity system and create a photon blockade to generate deterministic emission of N-photon bundles. The successful outcome of this action will be the first experimental realization of a high-fidelity N-photon emitter and is expected to boost research in various interdisciplinary areas from bio-imaging to photonic quantum simulation.