Sussex University is dropping its traditional chemistry degree, renaming the department and cutting the staff from 14 to seven.
Sussex University is renaming the department and cutting staff
Dr Gerry Lawless, head of the chemistry department, now named chemical biology, said the move was "ludicrous".
The university said the department had lost researchers and had no guarantee of sustained or viable student numbers.
The Royal Society for Chemistry criticised the move saying it created a void that will affect the whole campus.
Dr Lawless said applications for undergraduate chemistry were up 40% on last year, with 350 applicants chasing about 25 places.
He claimed top-quality applicants would not want to study at the new department and staff would leave.
He also said a chemical biology degree would not have the breadth of traditional chemistry, and said: "Employers want people with a good grounding in chemistry and a minor in chemical biology."
A university statement said it was difficult, nationally, to recruit undergraduate students in chemistry, and that researchers had left to work at larger departments.
It said: "While applications have shown a welcome growth this year, due our league table standings, there is no guarantee this would lead to sustained and viable numbers."
Retaining the existing department would cost an extra £750,000 with no guarantee of long-term success in recruitment or research, it added.
The University of Sussex will instead concentrate on other areas including English, history, media, and maths.
The Royal Society for Chemistry's chief executive Dr Richard Pike said: "No university can claim to be a real university without chemistry.
"It is the central science in the absence of which there is a void that affects a campus."