Every day from morning till evening (or even late night) we use different switches. Mainly electrical ones. In the simplest case, these useful devices allow us to switch something between two different states, for example, light on - light off. More complicated switches provide wider range of available modes. But what does the word "switch" mean in relation to a molecule? Basically, the meaning is the same: a molecule-"switch" can reversibly change its structure between two or more different forms. Like in case of "normal" switches, the molecular switch needs some external energy to perform the switching. In daily life, we use our finger as a source of energy when pressing a button. In the case of molecules, different external stimuli such as heating, light irradiation, changes of acidity, electrical current etc. can be used as an energy source for switching. If our molecule nicely and reversibly changes its structure upon irradiation with light, it is called "photoswitch". The following video shows how the compound I am working with can be switched from "orange" to "red" state by irradiation with blue LED.
