Possibility of any excimer/aggregate formation of SPANI in aqueous medium at high concentrations of the polymer was excluded based on the concentration dependent measurements of the fluorescence emission spectra. Temperature dependent measurements of the fluorescence emission spectra of SPANI in aqueous medium indicated the possibility of dual fluorescence from two closely lying singlet (S1) excited conformations. Again, pH dependent measurements of steady state absorption and fluorescence emission spectra suggested the co-existence of two ground state conformations ('A' and 'B') of SPANI. The conformation 'A' arises due to sixmembered ring formation by H-bonding between the H atom of the sulfonic acid group and N atom of the amine group. However, the conformation 'B' arises due to abstraction of one H atom from the solvent by the amine group. The conformation 'B' was found to be relatively less stable than the conformation 'A' in the ground state. Also, it was suggested that population of conformation 'A' is more than that of conformation 'B' in less acidic medium, while the reverse is true in more acidic medium. Obviously, in normal working low acidic (pH = 4.5) aqueous medium, contribution from conformation 'A' was found to be more than that of conformation 'B' in the fluorescence emission spectra. These findings were corroborated by the data obtained from the time-resolved measurements. Moreover, excitation wavelength dependent measurements of the fluorescence emission spectra of SPANI in aqueous medium revealed combined red-edge effect (REE) from the two conformations of SPANI.