Who invented tranquilizers?

Tranquilizers, specifically benzodiazepines, were first developed by Swiss chemist Leo Sternbach in the 1950s. The first of these medications, chlordiazepoxide, was introduced in 1960 under the brand name Librium. Benzodiazepines quickly became popular for their sedative and anxiolytic effects, leading to the development of many other similar drugs. Prior to this, other types of sedatives, such as barbiturates, were commonly used.