Fig. 4. Time-resolved fluorescence decay of 1c (solid line) in toluene, CH₂Cl₂ and benzonitrile and of 3c (dashed line) in toluene (see the ESI† for data of 3c in CH₂Cl₂ and benzonitrile). Inset: the crossing of the fluorescence decay curves of 1c in toluene and CH₂Cl₂.