The Nobel Prize in Chemistry was jointly awarded to U.S.-based scientist David MacMillan and Benjamin List of Germany for their work developing a new tool for producing molecules with a range of useful applications.

Dr. MacMillan of Princeton University and Dr. List of the Max-Planck-Institut für Kohlenforschung in Mülheim an der Ruhr had developed an “ingenious tool for building molecules” called organocatalysis, the Royal Swedish Academy of Sciences said when announcing the prize on Wednesday.

Scientists...

The Nobel Prize in Chemistry was jointly awarded to U.S.-based scientist David MacMillan and Benjamin List of Germany for their work developing a new tool for producing molecules with a range of useful applications.

Dr. MacMillan of Princeton University and Dr. List of the Max-Planck-Institut für Kohlenforschung in Mülheim an der Ruhr had developed an “ingenious tool for building molecules” called organocatalysis, the Royal Swedish Academy of Sciences said when announcing the prize on Wednesday.

Scientists use catalysts to drive chemical reactions, but only two kinds of catalyst—metals and enzymes—were known to exist before the two men, working independently of each other, developed a third type of carbon-based catalyst in 2000.

Their discovery “has had a great impact on pharmaceutical research, and has made chemistry greener” by using naturally occurring organic molecules, the academy said.

“It’s a great gift that nature provides these molecules for us,” said Dr. List, answering reporters’ questions by phone during a press conference.

The field has developed rapidly over the past two decades, Dr. List said, increasing the power and efficiency of “these extremely reactive organocatalysts.” That has enabled their use in an increasingly wide range of chemical processes, from the development of pharmaceuticals to the production of light-absorbent material for solar cells.

Organic catalysts typically combine carbon atoms with other common elements such as oxygen, nitrogen and sulfur. While the efficacy of organocatalysis is clear, scientists still don’t fully understand how some aspects of the process work, Dr. List said.

The winners equally share the prize of 10 million Swedish kronor, equivalent to about $1.13 million.

It isn’t clear whether Dr. MacMillan, who was born in the U.K., is aware of his prize. Göran Hansson, the academy’s secretary general, said that he hadn’t been able to reach Dr. MacMillan by phone, and had so far only managed to send him an email and leave a voice mail with the news.

Write to Trefor Moss at Trefor.Moss@wsj.com