Dr Sinha's major contributions lie in the field of Solid State Chemistry. He has made extensive studies on the synthesis of new manganites and their structural, electrical and magnetic properties. He has developed theories for thermoelectrical power and mobility in such semiconductors. His studies on electron lattice interaction have furnished a new basis for the theory of ferro-electricity. From his studies on thin film of heterojunctions, Dr Sinha has discovered interesting properties which throw new light on the mechanism of conduction in semiconductors. The products developed by him have found practical application in the electronics industry.