Figure shows the transient absorption spectra of SPANI in aqueous medium (concentration: 0.3 mg ml -1 ) at different delay times (up to 1 ns) following excitation (pump) at 320 nm (π-π* transition due to the benzenoid unit, S0 → S1). Clearly, upon excitation, fast (apparently within a few hundred fs) excited state absorption (ESA) from the S1 state of SPANI to higher electronic states (Sn, n = 2,3,4,….) gives rise to broad transient absorption spectra in the spectral region 425-575 nm (approximately), which then decays in the fs-ps time scale due to depopulation of the S1 state. Apparently, the broad transient absorption spectra consist of two bands. At shorter delay times, both the bands are weak and broadly overlapping, which makes it difficult to determine the exact peak positions of the two bands. However, at longer delay times, as the band on the red side of the spectra is almost completely decayed, the peak position of the band on the blue side of the spectra becomes clear (about 474 nm). On the other hand, looking at the spectra at 650 fs delay time, the peak position of the band on the red side of the spectra may be assigned to be at about 530 nm (as the contribution from the other band is relatively weak on the red side of the spectra at this delay time). Figure shows similar features as figure except that the two bands on the blue and red sides of the spectra are apparently resolved better in the former one. Accordingly, the peak positions of the bands on the blue and red sides of the spectra are assigned to be at about 471 nm and 530 nm, respectively (based on Fig. ).