© 2023 Wiley Periodicals LLC.Herein, a novel D-A-D type monomer that contains hexylthiophene as the donor and benzo[c][1,2,5]thiadiazole as the acceptor has been electropolymerized successfully to yield P(DTFBT) and its electrochromic properties and performance in amperometric biosensors have been investigated. The polymer shows great electrochemical features with low band gap and multichromic properties. Additionally, after polymer modification, laccase was immobilized on a modified electrode surfaces for catechol sensing. Biosensor optimization values, cycle number, enzyme amount, pH and also interfering effect of some possible compounds were investigated. With optimum values, analytical characterization of the sensor was determined. Kmapp, LOD and sensitivity values were estimated as 0.11 mM, 0.014 mM and 166.74 μA/(mM cm2), respectively. The experimental results revealed that the sensor shows satisfactory accuracy and confirms the proposed sensor has a potential candidate for catechol quantification.