The prime objective of the present work is to investigate the sub-ns (or ultrafast) photophysical properties of SPANI in aqueous medium by carrying out femtosecond (fs) transient absorption measurements based on pump-probe technique. The present findings are extremely important keeping in view various commercial applications of SPANI in the field of polymer optoelectronics. It is to be mentioned that till date, to the best of our knowledge, only a few literature data are available on the ultrafast spectroscopy of PANI . Kim et al. reported ultrafast pump-probe spectroscopic measurements of primary and secondary doped forms of PANI in solution to investigate the relaxation dynamics of photoexcited carriers and established that the excited carriers relax nonradiatively to the ground state via an intermediate state with a twisted geometry. Using fs pump-probe transient absorption measurements, Menšik et al. observed and theoretically explained the ultrafast dynamics of excited state, charge transfer state and polaron state of emeraldine base form of PANI in solution.