William Motherwell is an organic chemist best known for his pioneering approach to molecular synthesis involving the invention of new reactions. His work has encompassed the chemistry of metallocarbenoid reactive intermediates, transition metal-mediated reactions, fluorination chemistry and a significant number of free radical chain reactions for the preparation of valuable natural products of biological interest.

In recent years, William has developed an innovative strategy to produce artificial enzymes, and also designed a unique top pan molecular balance to measure the noncovalent interactions responsible for molecular recognition.

The recipient of numerous international awards, William has won the Corday–Morgan Medal, the Bader Award and the Tilden Medal and Lectureship of the Royal Society of Chemistry. He received the Silver Medal of the French Natural Product Chemistry Institute (ICSN) in 2000. Elected a Fellow of the Royal Society of Edinburgh in 2007, he is currently Alexander Williamson Professor Emeritus of Chemistry at University College London.