A Divergent Alkyne Diol Directs [2 + 2] Photoreactivity in the Solid State: Cocrystal, Supramolecular Catalysis, and Sublimation Effects.

2-butyne-1,4-diol () is used as a divergent ditopic template that directs -1,2-bis (pyridyl) ethylene (, where = ' = 3 or 4) to undergo an intermolecular [2 + 2] photodimerization in the solid state. The components of cocrystals [()·()] and [()·()] form 1D hydrogen-bonded polymers with assembled as infinite parallel stacks. The alkenes undergo [2 + 2] photocycloadditions to form -tetrakis (-pyridyl) cyclobutane (where = 3 or 4). We demonstrate that the reactive solid involving exhibits supramolecular catalysis.