Together with Henry Eyring and Michael Polanyi, Meredith Gwynne Evans is one of the founders of the transition state theory.

[1] One of MG's brothers, AG Evans, worked with him and later took the chair of chemistry at University College Cardiff, beating off the challenge of E. A. Moelwyn-Hughes.

In this research field, he worked with Douglas Hartree and Lawrence Bragg to apply quantum mechanics to chemical problems.

In 1933, M. G. Evans was awarded a Rockefeller Scholarship and went to Princeton University to work with Hugh Taylor and Henry Eyring, amongst others.

Back in Manchester, Evans became one of Michael Polanyi's principal coworkers on the development of the transition state theory.