Photoreactive salt cocrystal: N + –H⋯N hydrogen bond and cation–π interactions support a cascade-like photodimerization of a 4-stilbazole

Hydrogen bonds ( i.e. , N + –H⋯N) in combination with cation⋯π interactions enable a cascade-like [2 + 2] photodimerization of 4-stilbazole in a salt cocrystal.