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The results of the gain spectra studied for six Coumarins with different substituents at the 4th and 7th positions are reported. These dye concentration dependent gain spectra have been studied by the amplified spontaneous emission (ASE) technique using an N 2 laser (337.1 nm) in the concentration range 1 10 -5 to 1 10 -2 M. The dyes are so selected that a comparative study could also be possible between rigid and nonrigid structures. All studies are made with a polar solvent. The observation of two bands in the gain spectra of nonrigid coumarin dyes in polar solvent (ethanol) is of great interest and the anomalous long wavelength peak formation is attributed to twisted intramolecular charge transfer (TICT) state formation in the excited state. The dominant stabilization of the TICT state is due to a long range specific polarization interaction with polar solvent molecules. The nonradiative decay path (ICT → TICT transition) is found to be dependent on the Coumarin structure and substituent pattern. The relationship between the short wavelength bands is also explained. The dependence of lasing wavelength and the peak gain on the dye concentration have also been correlated with the variation of fluorescence life time which is due to radiation trapping and concentration quenching.