In DCM, the instantaneous 570 nm ESA band is again observed with a grow-in of ESA at 860 nm within 30 ps which decays with a lifetime of 6.7 ns (Supplementary Fig. ), consistent with the fluorescence lifetime of 5.6 ns (Supplementary Table ). The longer formation time could be due to the higher viscous drag of the DCM solvent shell reorganisation compared with MCH, and increased CT nature of the large delocalised mixed LE/CT excited state in DCM. At the other extreme, Cz-PI in MCH (Supplementary Fig. and) also has an instantaneous ESA at 560 nm followed by the emergence of a sharp ESA band at 750 nm within ca. 400 fs.