Florian Römpp works on a project, that revolves around the development of thermally bistable photochromic diarylethene-based pKa-modulators, operating in physiological systems. Due to the non-invasive nature and spatiotemporal resolution of light as the stimulus, these switches represent a versatile and efficient tool in the external regulation of reactions and microenvironments, as well as the investigation and control of pH-dependent processes, chemical and biological systems, proton-gradients and membrane potentials.