The use of colloidal nanocrystals in photoredox catalysis, e.g., as part of artificial photosynthetic systems, has recently gained significant attention, owing to their strong light absorption and tunable electronic and optical properties. In many relevant reactions, several charge carriers are needed, and efficient charge carrier accumulation has to be achieved at reaction centers. To manage the challenging task to design materials optimized to drive multi charge-carrier processes, we are investigating charge carrier dynamics in colloidal nanocrystals involving single and multiple excitations of nanocrystals. Currently we are developing strategies to investigate simultaneous or consecutive charge carrier transfer processes. First steps applying transient absorption spectroscopic studies revealing the dynamics of single and multiple excitons will be presented.