In 1964, Rahman joined the Karachi University as a lecturer in undergraduate chemistry. He remained associated with the Cambridge University between 1969 and 1973, and is presently honorary Life Fellow at the King's College of the Cambridge University. In 1977, he became the co-director of the Hussain Ebrahim Jamal Research Institute of Chemistry at University of Karachi; eventually he was ascended as the Director in 1990. In 1979, Rahman did the post-doctoral research at the University of Tübingen. Upon returning to Pakistan, he joined Karachi University where he lectures and taught chemistry. He was appointed Professor Emeritus at University of Karachi for life.
He carried out important studies on the synthesis of anti-cancer alkaloids present in the plant Catharanthus roseus and analytical studies on organic compounds involving circular dichroism and is generally recognized as bringing a huge positive change in the development of science and technology as well as higher education in Pakistan.
His book entitled "Stereoselective Synthesis in Organic Chemistry" (Springer-Verlag) was termed a monumental contribution in the field by the Nobel Laureate Sir Derek Barton in the foreword of the book written by him. His book entitled "NMR Spectroscopy-Basic Principles" was published by Springer-Verlag and translated into Japanese for use in university courses in Japan   The Nobel Laureate Herbert C. Brown applauded the contributions of Rahman in science and technology.