“…The product should be kept at −20°C in a refrigerator; otherwise, it will be soon decompose to a black solid. mp = 115−117°C; 1 H NMR (400 MHz, CDCl 3 ) δ 7.18 (s, 2H); 13 . In a dry two-necked flask, benzo[1,2-b:4,5-b′]dithiophene-4,8-dione (5.5 g, 25 mmol) was dissolved in freshly distilled THF (150 mL).…”