## 3 Materials and Methods
#### Synthesis of the Starting Substrates
Available online: www.ccdc.cam.ac.uk/structures; accessed on 8 September 2023; for details, see Supplementary Materials.) _6,7-Difluoro-2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3 af**). A yield of 0.252 g (72%), 6.5 h, gray solid. Mp. = 221-222 \({}^{\circ}\)C (DMAC/H\({}_{2}\)O). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 12.72 (br.s, 1H), 11.66 (s, 1H), 8.51-8.47 (m, 1H), 8.18 (s, 1H), 7.54-7.50 (m, 1H), and 7.26-7.11 (m, 4H) ppm; \({}^1H), 7.58-7.51 (m, 2H), 7.26-7.16 (m, 4H), and 3.97 (s, 3H) ppm; \({}^{13}\)C\({}^{\{1}\)H\(\}\) NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 149.8, 143.1, 136.0, 135.9, 126.6, 126.3, 122.2, 121.4, 121.2, 120.0, 118.1, 111.6, 109.5, 105.1, and 31.3 ppm. _2-(1H-indol-3-yl)-1-isopropyl-1H-benzo[d]imidazole_ (**3 ah**). A yield of 0.311 g (87%), 6 h, white solid. Mp. = 257-258 \({}^{\circ}\)C, decomposition (DMAC/H\({}_{2}\)O). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 11.68 (brs, 1H), 7.94 (d, \(J\) = 8.0 Hz, 1H), 7.78-7.74 (m, 2H), 7.69-7.65 (m, 1H), 7.53 (d, \(J\) = 8.0 Hz, 1H), 7.24-7.13 (m, 4H), 5.07-4.96 (m, 1H), 1.63 (s, 3H), and 1.62 (d, \(J\) = 6.8 Hz, 3H) ppm; \({}^{13}\)C\({}^{\{1}\)H\(\}\) NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 148.9, 144.0, 136.0, 133.2, 126.6, 126.4, 122.0, 121.1, 121.0, 120.2, 120.0, 118.8, 112.1, 111.8, 105.1, 48.0, and 20.9 ppm. HRMS (ESI) calcd for C\({}_{18}\)H\({}_{18}\)N\({}_{3}\) [M+H]\({}^{+}\) 276.1495; found 276.1505. _1-Alllyl-2(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3 ai**). A yield of 0.188 g (53%), 14 h, light-beige solid. Mp. = 213 \({}^{\circ}\)C, decomposition (petroleum ether/EtOAc). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 11.68 (brs, 1H), 8.36 (d, \(J\) = 7.6 Hz, 1H), 7.84 (brs, 1H), 7.72-7.70 (m, 1H), 7.53-7.47 (m, 2H), 7.25-7.16 (m, 4H), 6.18-6.09 (m, 1H), 5.21 (d, \(J\) = 10.4 Hz, 1H), 5.07-5.05 (m, 2H), and 4.92 (d, \(J\) = 17.2 Hz, 1H) ppm; \({}^{13}\)C\({}^{\{1}\)H\(\}\) NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 149.4, 143.1, 136.0, 135.3, 133.4, 126.4, 125.9, 122.2, 121.4, 121.3, 120.1, 118.3, 116.2, 111.6, 109.8, 104.6, and 46.1 ppm. HRMS (ESI) calcd for C\({}_{18}\)H\({}_{16}\)N\({}_{3}\) [M+H]\({}^{+}\) 274.1339; found 274.1327. _1-Benzyl-2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3 aj**) [67]. A yield of 0.361 g (86%), 6.5 h, white solid. Mp. = 230-231 \({}^{\circ}\)C (DMAC/H\({}_{2}\)O), lit. [67] 232-234 \({}^{\circ}\)C). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 11.59 (brs, 1H), 8.39 (d, \(J\) = 7.6 Hz, 1H), 7.73 (d, \(J\) = 8.0 Hz, 1H), 7.67 (d, \(J\) = 2.0 Hz, 1H), 7.49 (d, \(J\) = 7.6 Hz, 1H), 7.45 (d, \(J\) = 8.0 Hz, 1H), 7.32-7.28 (m, 2H), 7.25-7.16 (m, 5H), 7.08 (d, \(J\) = 7.6 Hz, 2H), and 5.73 (s, 2H) ppm; \({}^{13}\)C\({}^{\{1}\)H\(\}\) NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 149.7, 143.2, 137.1, 135.9, 135.6, 128.7, 127.2, 126.4, 125.9, 125.8, 122.3, 121.5, 121.6, 121.4, 120.2, 118.4, 111.6, 109.9, 104.7, and 47.0 ppm. _2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3 ah**) [68]. A yield of 0.386 g (96%), 14 h, purple solid. Mp. = 224-225 \({}^{\circ}\)C (EOH, lit. [68] 223-224 \({}^{\circ}\)C). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 11.40 (brs, 1H), 8.47-8.44 (m, 1H), 7.77 (d, \(J\) = 8.0 Hz, 1H), 7.70-7.63 (m, 3H), 7.56-7.52 (m, 2H), 7.45-7.41 (m, 1H), 7.30-7.26 (m, 1H), 7.22-7.16 (m, 3H), 7.05 (d, \(J\) = 8.0 Hz, 1H), and 6.68 (d, \(J\) = 2.8 Hz, 1H) ppm; \({}^{13}\)C\({}^{\{1}\)H\(\}\) NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 149.1, 142.5, 136.6, 136.5, 135.6, 130.2, 129.3, 128.0, 126.2, 126.0, 122.3, 122.2, 121.6, 120.3, 118.0, 111.6, 109.5, and 104.5 ppm. _Bis[2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3 ah**) [68]. A yield of 0.386 g (96%), 6 h, gray solid. Mp. = 280 \({}^{\circ}\)C, decomposition (DMAC/H\({}_{2}\)O).