Steady-state absorption, emission, and time-resolved spectroscopy were utilized to study the dynamics of excited states of linear and multi-branched bithiazole derivatives in different solvents at room temperature. In the studied compounds, triphenylamine and bithiazole groups act as donor and acceptor, respectively. BTZ-I and II have similar linear molecular structures, while BTZ-III and BTZ-IV have multi-branched structures. The difference is that the donor and acceptor units are connected by a single bond or a triple bond, respectively. With increase in solvent polarity, the fluorescence spectra exhibit a red shift and the fluorescence lifetime increases. Our results suggest there is intra-molecular charge transfer (ICT) processes in these four samples.