Rao was one of the earliest to synthesise two-dimensional oxide materials such as La2CuO4. He was one the first to synthesise 123 cuprate, the first liquid nitrogen-temperature superconductor in 1987. He was also the first to synthesis Y junction carbon nanotubes in the mid-1990s. His work has led to a systematic study of compositionally controlled metal-insulator transitions. Such studies have had a profound impact in application fields such as colossal magneto resistance and high temperature superconductivity. Oxide semiconductors have unusual promise. He has made immense contributions to nanomaterials over the last two decades, besides his work on hybrid materials.