A team of researchers from Institut Lumière Matière, Universität Heidelberg and Leiden University has found via study of a whole class of polycyclic aromatic hydrocarbons (PAHs) that such molecules follow the same relaxation pathways and have size-dependent lifetimes—and behave more like solids than is typical for molecules. In their paper published in the journal Nature Physics, the group describes their work, which involved studying what happens when ultrashort X-rays are fired at large and complex molecules. Laura Cattaneo with the Max Planck Institute for Nuclear Physics has written a News and Views piece outlining general work involved in trying to understand photochemistry in complex big molecules and the work done by the team on this new effort.