Carbazole-based conjugated polymers are promising candidates for electrochromic supercapacitors, but the structure–property relationship between linear and star-shaped architectures remains insufficiently understood. In this work, a linear carbazole-EDOT polymer (pCbz-2E) and a star-shaped carbazole-EDOT polymer (pCbz-3E) were synthesized via Pd-catalyzed Stille coupling and then electropolymerized on ITO electrodes to form uniform films with comparable thicknesses. Their spectroelectrochemical, electrochromic, and capacitive performances were systematically compared. Compared with pCbz-2E, pCbz-3E exhibited a comparable optical contrast but faster switching, higher coloration efficiency, and better electrochromic cycling stability. In supercapacitor tests, pCbz-3E delivered a higher volumetric capacitance (183.8-142 F/cm³ at 2-50 A/cm³) than pCbz-2E (103.4-95 F/cm³), with 40.9% capacitance retention after 10000 cycles. The improved performance is attributed to the star-shaped architecture, which produces a looser, porous, network-like morphology, lower charge-transfer resistance, faster ion diffusion, and higher capacitive contribution. These results provide a universal design strategy for developing high-performance carbazole-based electrochromic supercapacitor materials. 

Electrochromic supercapacitor, Carbazole-based, Star-shaped polymer, Electropolymerization, High performance