The same year, he moved to the University of Minnesota, where he completed a PhD under the supervision of Regents' Professor Paul G. Gassman (while also collaborating with Jan Almlöf) in 1992 and subsequently also postdoctoral research with Lawrence Que Jr. During this period, Abhik reported some of the first high-quality ab initio and density functional theory calculations on bioinorganic systems, helping lay the foundation of the now thriving field of computational bioinorganic chemistry.

He did a brief, second postdoc with David Bocian at the University of California Riverside, in the course of which he derived significant new insight into the problem diatomic ligand discrimination by heme proteins.

He has had several secondary positions/affiliations: Senior Fellow of the San Diego Supercomputer Center[4] at the University of California San Diego (1997–2004), Outstanding Younger Researcher awardee of the Research Council of Norway (2004–2010), a co-principal investigator at the national center of excellence Centre for Theoretical and Computational Chemistry (2007–2017), and a visiting professor at the University of Auckland, New Zealand, on many occasions (2006–2016).

Early in his career, Ghosh used X-ray photoelectron spectroscopy (XPS) to study short-strong hydrogen bonds in porphyrin-type molecules.

Despite their size-mismatched character, many of these complexes have proved rugged and found applications as near-IR phosphorescent photosensitizers in oxygen sensing[32][33] and photodynamic therapy as well as in dye-sensitized solar cells.

[38] Ghosh has also published popular articles on arrow pushing,[39] on the occasion of the 100th anniversary of its first use by Sir Robert Robinson, and on the impact of relativity in chemistry,[40] among many others.

In 2020–2021, Ghosh published two biographical essays[41][42] on the late Martin Gouterman, a noted porphyrin chemist and one of the first openly gay/LGBT scientists, drawing a parallel with astronomer and gay rights activist Frank Kameny (see LGBT history for a more general discussion).