The activation of C-H and Si-H bonds remains one of the major challenges in modern synthetic chemistry. Photoinduced activation of these bonds by transition metal complexes represents a powerful and promising option for future syntheses. Time-resolved X-ray spectroscopy of such complexes provides insights into the electronic structure changes of these compounds and thus allows for a better understanding of the underlying mechanisms and electronic interactinos. Theoretical calculations of time-resolved XAS and RIXS spectra are essential for the interpretation of the measured data.