Regulating photoreactivity in a polymorphic bi-component solid through large synthons.

Polymorphism in bi-component crystals has received immense attention in recent times due to their potential in property engineering. Two polymorphs of a functional bi-component molecular solid are derived using Long-range Synthon Aufbau Modules (LSAM) by tuning the nature and position of substituents. The two polymorphs show distinct photochemical properties; Form I undergoes partial cis-trans isomerization, and Form II sustains a [2 + 2] photodimerization. The polymorphic forms also exhibit different photomechanical behaviors. While Form I shows differing photomechanical responses upon UV irradiation based on crystal morphology, Form II undergoes a solid-to-liquid transition upon photo-irradiation.