This contribution gives an overview of our recent effort to probe catalytic solid-liquid interfaces in situ and to investigate recognition processes at chiral surfaces. Attenuated total reflection infrared spectroscopy in a dedicated low volume flow-through cell is used to investigate the working catalytic interface. The latter technique is combined with modulation spectroscopy, which relies on the perturbation of the system under investigation by a periodically varying external parameter. A digital phase-sensitive detection results in high quality spectra. The method furthermore yields kinetic information and helps disentangle complex spectra. The described tool is therefore ideally suited for the investigation of complex systems. Applications in the fields of heterogeneous catalysis and recognition at chiral solid-liquid interfaces are presented. Our aim is a better molecular level understanding of these processes and, based on this knowledge, a rational design of better catalyst materials.