We present a comprehensive photophysical and photochemical characterization of a newly synthesized donor-acceptor (DA) substituted fluorene, 3,3'-(2-(benzo[d]thiazol-2-yl)-7-(diethylamino)-9H-fluorene-9,9-diyl)dipropanen itrile (1), of interest for nonlinear optical application. The charge-transfer nature of the low-energy transition of 1 was determined based on absorption, fluorescence and excitation anisotropy spectra collected at room temperature in organic solvents of different polarity. As expected for a charge-transfer DA dye with a largely neutral ground state, absorption spectra are marginally solvatochromic while fluorescence spectra show a sizable solvatochromism. Fluorescence lifetime measurements reveal monoexponential decay kinetics in all solvents. The values of the photostability quantum yield of 1 in different solvents were determined by the absorption method. The data showed that 1 has relatively high photostability, which is crucial for its practical application. Degenerate two-photon absorption spectrum of 1 was determined in a broad spectral range using open aperture Z-scan methodology and 1 kHz femtosecond excitation. The nature of ultrafast relaxation processes in the excited electronic states of 1 was investigated by femtosecond transient absorption pump-probe spectroscopic technique and two different types of fast relaxations with the characteristic times of 0.5 - 1.0 ps and 5 - 8 ps were detected. Efficient superfluorescence properties of 1 were observed in liquid medium under transverse pumping by femtosecond laser beam. Obtained results, supported by an extensive theoretical characterization, reveal a high potential of 1 for application in a number of nonlinear optical techniques, including two-photon laser scanning fluorescence microscopy. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement n°607721.