A new donor-acceptor-donor type polymer called poly(3,9-(3,3-didecyl-3,4-propylenedioxythiophene)-5,11-di-hydroindolo[3,2-b] carbazole) (P1) was synthesized and characterized electrochemically, spectro-electrochemically and colorimetrically. P1 shows multielectrochromic property; it is yellow in neutral state, and it changes color from yellow to khaki upon oxidation. Further oxidation causes the khaki color to turn green and then green to cyan, and upon reduction, the color changes from yellow to orange. P1 also has capacitance property and is soluble in common organic solvents. Its band gap was also electrochemically determined as 1.38 eV from cyclic voltammetry and 1.50 eV from differential pulse voltammetry, while optically, it was determined as 1.56 eV.