Shining light on a pentacene derivative: The role of photoinduced cycloadditions

Dimerization in a butterfly fashion: a soluble pentacene derivative undergoes photoinduced dimerization upon exposure to UV and visible light, both in solution and in the solid state. This pathway of degradation does not involve oxygen or moisture. Strategies to limit the damage require use of highly crystalline thin films or storage as a solution in benzene, which cooperatively interacts with the pentacene core, hampering the dimerization process.