Mathur's researches were focused on the organometallic chemistry of mixed metal cluster compounds and he has developed synthetic strategies for introducing chalcogen bridges. At IIT Mumbai, he handled projects related to the investigation of unusual metal mediated transformations and the interactions between the metal atoms and unsaturated organic species. He has published his researches by way of chapters contributed to books authored by others and over 180 peer-reviewed articles; ResearchGate and Google Scholar, two online repositories have listed several of them. He has also guided 22 doctoral scholars in their studies.
Mathur was a Fulbright scholar in 1995 and the Indian Academy of Sciences elected him as a fellow in 1996. The Council of Scientific and Industrial Research awarded him the Shanti Swarup Bhatnagar Prize, one of the highest Indian science awards, in 2000. He has also been honoured with an honorary D.Sc. degree by the University of Keele in the U.K.