2.2.5. Synthesis of TTF-py2 (the Mixture of cis and trans Isomers)

**4** (2.0 g,10 mmol) was suspended in 10 mL dehydrated toluene and 10 mL dehydrated P(OEt)3 under N2 atmosphere. This suspension was heated to 105 ◦C for 4 h. Red precipitate was filtered, washed with MeOH, and recrystallized with nitromethane to acquire red crystalline solid. 1H NMR (500 MHz, CDCl3, 298 K, ppm) δ 8.63 (2H), 7.77 (1H), 7.47 (2H). Since two structural isomers are produced in the synthesis of TTF-py2 (cis-TTF-py2 and trans-TTF-py2), we had difficulty in assigning the correct coupling from this NMR spectrum. Anal. Calcd for C16H10N2S4: C, 53.60; H, 2.81; N, 7.81; S, 35.77. Found: C, 53.21; H, 2.85; N, 7.99; S, 35.44.
