Optochemical genetics (OCG) merges small light-sensitive synthetic ligands with native or genetically engineered transmembrane proteins. In this video, we demonstrate the interdisciplinary nature of our research by combining the chemical synthesis of our specifically tailored molecules with their application in a biological context. As an example, electrophysiological recordings are performed in an acute brain slice preparation. In this experiment, repeated illumination of a light-switchable glutamate derivative translates into light-dependent action potential firing.