In the world scenario understanding radiation chemistry in the time domain of hundreds of nano seconds to milliseconds started with the inception of pulse radiolysis technique. In India also research on time-resolved radiation chemistry started after the linear accelerator based pulse radiolysis system was set up in 1986 in Chemistry Division of Bhabha Atomic Research Centre. In the initial years the basic understanding of the mechanisms underlying redox reactions of organic compounds was the main area of research. The basic thrust was in characterizing the transients, determination of redox potentials, rate constants, ionic equilibria, etc.