After graduation, Ibers accepted a staff scientist position at Shell Development Company and later Brookhaven National Laboratory. Starting in 1965 until his retirement, Ibers was a professor of chemistry at Northwestern University. His broad research interests included many aspects of organometallic, bioinorganic, and solid state chemistry,. Ibers was a noted pioneer in the applications of X-Ray Crystallography to chemical problems and issues associated with inorganic bonding.