Abstract: Four dithiophene quinoxaline type monomers (P1, P2, P3, P4) were synthesized by the reaction of dithiophenebenzothiadiazole with 5, 6-dione-1, 10-phenanthroline, phenanthrenequinone, acenaphthenequinone and benzil. Dithiophenebenzothiadiazole was prepared by stille coupling reaction using Pd(PPh₃)₂Cl₂ as catalyst. Four type polymers were synthesized by oxidative polymerization of dithiophene quinoxaline derivatives using anhydrous FeCl₃ as oxidant. All monomers and polymers were characterized by FT-IR and ¹H-NMR spectra. The optical properties of polymers solution in CHCl₃, at neutral state and when different concentrations of TFA was added into the solution, were investigated by UV-Vis-NIR and fluorescence spectrometer. Results show that P2-P4 have good sensitivity to low concentration of TFA, wherein polymer P2 is sensitive to 8.0×10^-4 mol/L of TFA. The polymer solution in CHCl₃ exhibites significant changes in color and there appears a new broad absorption band in the range of 600-1 100 nm. P2-P4 have certain fluorescence properties, and the fluorescence intensity decreases and emission wavelength exhibits blue shift when certain concentration of TFA is added to the polymer solution, wherein polymer P2 has sensitivity to 8.0×10^-6 mol/L of TFA.