These tiny molecular "light switches" change their structure when they are irradiated with light - similar to a switch that changes between "on" and "off". The ability to switch molecules in a targeted manner opens up prospects for applications in medicine, materials science and data storage. You can think of photo switches as a roller coaster with two switches: the left side goes fast, the right side goes slow. Copyright: Maximilian WutscherUnderstanding and predicting molecular switches For a long time, it was unclear why certain molecules behave in one way or another. "This makes it possible to specifically develop new molecules with tailored switching properties without having to rely on pure trial and error."