A facile polymer consisted of quinoline, thiophene and benzothiazole groups was designed and synthesized by Suzuki coupling reaction. The study of photophysical property indicated that the polymer was a red light emitter with maximum absorption (490nm) and emission (610nm) peaks. The assays of thermal gravimetric analysis (TGA) and cyclic voltammetry (CV) revealed that the polymer possesses good thermal (Td, 228°C) and electrochemical properties. The experimental data based on the cyclic voltammetry were in good agreement with the results of theoretical calculations. The sensing processes of the polymer to metal ions were investigated by UV–vis absorption and fluorescence emission spectra. The results showed that the polymer had high selectivity and sensitivity for Hg(II) ions with an obvious “turn-on” fluorescence in the presence of Hg(II). Noticeably, the polymer as a fluorescence probe can be applied in the detection in practical samples. The attribution of the work lies in providing a new strategy for design and application of polymer probes in analysis and testing fields.