Using the crossed-beam velocity map imaging technique that we have developed over several years, we investigate the dynamics of prototypical ion-molecule reactions. The goal of this research is to unravel the multidimensional dynamics of systems with several different degrees of freedom. Important model systems are charge transfer reactions and nucleophilic substitution reactions. In the focus of our studies are quantum scattering resonances in few-body collisions and the coupling of spectator vibrational modes to the reactive degrees of freedom. With this work we could unravel several distinct reaction mechanism in good agreement with multi-dimensional chemical dynamics simulations. Funded by the European Research Council (ERC project DoMInIon) we focus in particular on quantum effects in ion-molecule reactions and develop a novel instrument to achieve superior resolution for crossed-beam scattering.