Influence of core-substitution on the ultrafast charge separation and recombination in arylamino core-substituted naphthalene diimides

► Novel results on arylamino core-substituted naphthalene diimide charge transfer dynamics. ► Photoinduced charge separation associated with twisting of donor moiety. ► Detailed analysis of dynamics via transient experiments and ab initio calculations. ► Substitution controls energy gap between charge separated state and ground state. ► The charge recombination dynamics is controlled via the energy gap.