Leo Sternbach (May 7, 1908 – September 28, 2005) was a Polish American chemist who is credited with first synthesizing benzodiazepines, the main class of minor tranquilizers.

[1] Sternbach was born on May 7, 1908, in Opatija, Kingdom of Hungary, Austro-Hungarian Empire, to an upper middle class Jewish family.

The family lived in modest conditions, in a rented four-room apartment on the third floor of the "Vila Jadran" (Villa Adriatic), near the pharmacy owned by Sternbach's father.

He is credited with the discovery of chlordiazepoxide (Librium), diazepam (Valium), flurazepam (Dalmane), nitrazepam (Mogadon), flunitrazepam (Rohypnol), clonazepam (Klonopin), and trimethaphan (Arfonad).

In 1963, its improved version, Valium, was released and became astonishingly popular: between 1969 and 1982, it was the most prescribed drug in America, with over 2.3 billion doses sold in its peak year of 1978.

With Moses Wolf Goldberg, Sternbach also developed "the first commercially applicable" method for synthesizing biotin.

[7][8] A book Good chemistry: The life and legacy of Valium inventor Leo Sternbach was published by McGraw-Hill in 2004.