## 2 Experimental Section
### Synthesis of Monomers and Polymers  
4.1 (\(E\))-3'-(2-(5,5\"-dibromo-[2,2':5',2\"-terthiophene]-3'-yl)vinyl)-4,4\"-bis(2-ethylhexyl)-2,2':5', 2\"-terthiophene (M1)  
(\(E\))-3'-(2-(5,5\"-dibromo-[2,2':5',2\"-terthiophene]-3'-yl)vinyl)-4,4\"-bis(2-ethylhexyl)-2,2':5', 2\"-terthiophene (M1). Compound 1 (1.9 g, 3.2 mmol) was taken in a 100 mL Schlenk flask and degassed via vacuum-nitrogen cycle by three times. 20 mL of anhydrous THF was added and stirred in an ice bath for several minutes and then added with sodium _tert_-butoxide (0.33 g, 3.4 mmol). After stirring for 30 min, Compound 2 (1.37 g, 2.7 mmol) which was dissolved in anhydrous THF (10 mL) was added. The reaction mixture was warmed to room temperature and stirred overnight. The solution was poured into ammonium chloride aqueous solution and extracted twice with 40 mL ethyl acetate. The organic phase was combined and dried with MgSO\({}_{4}\). After removal of the solvent, the residue was purified by flash column chromatography (eluent: Hexane, \(R_{\text{f}}\) = 0.4), yielding a yellow liquid M1 (1.3 g, 1.5 mmol, 56%) \({}^{1}\)H NMR (500 MHz, CDCl\({}_{3}\)) \(\delta\) 7.24 (s, 1H), 7.23 (d, \(J\) = 15.8 Hz, 1H), 7.20 (s, 1H), 7.07 (d, \(J\) = 15.8 Hz, 1H), 7.05 (d, \(J\) = 3.8 Hz, 1H), 7.01 (s, 1H), 6.98 (s, 1H), 6.95 (s, 1H), 6.94 (d,\(J\) = 3.8 Hz, 1H), 6.90 (d, \(J\) = 3.8 Hz, 1H), 6.88 (d, \(J\) = 3.8 Hz, 1H), 6.79 (s, 1H), 2.61-2.51 (m, 4H), 1.62-1.56 (m, 2H), 1.40-1.26 (m, 16H), 0.92-0.87 (m, 12H); \({}^{13}\)C NMR (125 MHz, CDCl\({}_{3}\)) 8 142.92, 142.81, 137.88, 137.04, 136.46, 136.27, 136.98, 135.63, 135.32, 134.54, 132.47, 130.69, 130.67, 130.38, 128.73, 127.18, 125.99, 124.42, 124.32, 122.46, 122.22, 122.14, 121.64, 120.44, 113.26, 111.70, 40.34, 40.22, 34.55, 34.52, 32.55, 32.46, 28.90, 28.86, 25.65, 25.60, 23.04, 14.14, 10.87, 10.83. 5-Octyl-1,3-di(thiophen-2-yl)-4\(H\)-thieno[3,4-\(c\)]pyrrole-4,6(5\(H\))-dione (4)  
Compound 3 (1.0 g, 3 mmol), tributyl(thiophen-2-yl)stannane (2.8 g, 7.5 mmol), and Pd(PPh\({}_{3}\))\({}_{4}\) (35 mg, 0.03 mmol) were weighted into microwave tubes (G30) and then 12 mL anhydrous toluene were added. The tubes were directly subjected into the microwave reactor and processed the reaction conditions: (1) raise temperature from r.t. to 30 \({}^{\circ}\)C in 3 min; (2) raise temperature from 30 to 200 \({}^{\circ}\)C as fast as possible; (3) hold the temperature 90 min; cool down to 55 \({}^{\circ}\)C. The crude product was filtered with Celite to remove the metal catalyst. After removal of the solvent, the residue was purified by column chromatography (Hexane/chloroform = 4/1), yielding a yellow solid 4 (1.138 g, 2.61 mmol, 86%). \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) 8 7.98 (d, 2H, \(J\) = 3.6 Hz), 7.41 (d, 2H, \(J\) = 5.0 Hz), 7.10 (dd, 2H, \(J\) = 3.6, 5.0 Hz), 3.63 (t, 2H, \(J\) = 7.2 Hz), 1.65 (m, 2H), 1.23 (m, 10H), 0.84 (t, 3H, \(J\) = 6.6 Hz); \({}^{13}\)C NMR (100 MHz, CDCl\({}_{3}\)) 8 162.51, 136.39, 132.41, 129.81, 128.56, 128.36, 38.54, 31.76, 29.67, 29.16, 28.46, 26.93, 22.59, 14.04. 4.3 1,3-Bis(5-bromothiopen-2-yl)-5-octyl-4\(H\)-thieno[3,4-\(c\)]pyrrole-4,6(5\(H\))-dione (M3)  
1,3-Bis(5-bromothiopen-2-yl)-5-octyl-4\(H\)-thieno[3,4-\(c\)]pyrrole-4,6(5\(H\))-dione (M3). A mixture of 5 (0.432 g, 1.01 mmol) and \(N\)-bromosuccinimide (0.394 g, 2.2 mmol) in 50 mL chloroform and 50 mL acetic acid stirred overnight at room temperature. Then, the solution was poured into water and extracted twice with 50 mL chloroform. The organic phase was combined and dried with MgSO\({}_{4}\). After removal of the solvent, the residue was purified by flash column chromatography (eluent: hexane/CH\({}_{2}\)Cl\({}_{2}\) = 6/1), yielding yellow solid M3 (0.50 g, 0.85 mmol, 85%).