[3] During his last years of his life, Iyenger engaged in peace activism and greatly exhorted the normalization of bilateral relations between India and Pakistan.
In 1956, Iyengar was trained in Canada working under Nobel laureate in Physics Bertram Neville Brockhouse, contributing to path-breaking research on lattice dynamics in germanium.
At the DAE, he built up and headed the team of physicists and chemists that gained international recognition for their original research contributions in this field.
When Ramanna took over as director of Bhabha Atomic Research Centre in 1972, the mantle of directorship of the Physics Group (PG) was handed over to Iyengar.
As director, one of his first tasks was to take charge of the construction of the Dhruva reactor, the completion of which was then in question, and bring it to a successful conclusion under his leadership.
He also initiated proposals for the export of heavy-water, research reactors, hardware for nuclear applications to earn precious foreign exchange.