Scientists from Queen's University, Belfast have taken the first and second slots in a list of top chemists.
Professor Ken Seddon, a director of the QUB's Ionic Liquids Laboratory (QUILL), came first in the UK on the the Times Higher Education Supplement listing of the 100 Top Chemists of the Past Decade.
He was ranked 46 overall in the world.
Dr John Holbrey, also from QUILL, took second in the UK and 59 in the world.
They are two of only four UK chemists to be listed.
The list is based on how often a chemist's work is officially cited or referred to.
Professor Seddon has made it his life's work to promote green chemistry around the world.
Ionic liquids are solvents consisting of electrically charged particles - or ions - which could be positive or negative.
They are not flammable, release no fumes and can help make chemical reactions faster and cheaper.
Professor Seddon was one of the founders of QUILL, which was set up as an industrial consortium at Queen's.
The laboratory provides research for many multinational companies, including Shell, Proctor and Gamble and Petronas.