A mixture of 1,5-Dihexyl-3,7-di-(5-bromothiophen-2-yl)-1H,5H-pyrrolo[2,3-f]indole-2,6-dione (0.150 g, 0.221 mmol), 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-di-ethylhexylfluorene (0.149 g, 0232 mmol), Pd2(dba)3 (5.0 mg), (o-tol)3P (3.0 mg), K3PO4 (0.187 g) and toluene/H2O (20 mL/1 mL) was heated at reflux for 24 h. 2-bromothiophene (0.035 g, 0.22 mmol) in toluene (1 mL) was added and the resulting mixture was stirred for another 12 h. Then, after cooling to room temperature, the mixture was dropped into methanol to precipitate. After being filtered and dried, the precipitation was Soxhlet extracted with methanol, acetone, hexane, dichloromethane and chloroform in succession. The chloroform solution was concentrated and reprecipitated in methanol. The solid was filtered and dried to yield polymer (0.165 g, 82.5%) as a blue-green solid.
