Ultrafast excited state dynamics of a stilbene–viologen charge transfer complex and its interaction with alkanediammonium salts

•Stilbene-Viologen supramolecular charge transfer complexes (D∙A) was obtained.•D∙A fluorescence ignition occurs upon adding alkanediammonium salts.•D∙A can be regarded as a possible optic sensor.•Times of electron transfer were measured by femtosecond transient spectroscopy.•Back electron transfer was described by semiclassical single-mode nonadiabatic theory.