An international research team led by Markus Gühr’s group at the University of Potsdam performed laser experiments at Deutsches Elektronen-Synchrotron DESY to monitor charge motions in light-excited molecules of thiouracil, which is a modified nucleobase. This class of molecules has a variety of medical applications, including possible novel cancer therapies. Their basic research now published in Nature Communications opens up the possibility to map the charge flowing inside the molecular landscape.