## 3 Materials and Methods
#### Synthesis of the Starting Substrates
HRMS (ESI) calcd for C\({}_{15}\)H\({}_{11}\)FN\({}_{3}\) [M+H]\({}^{+}\) 252.0932; found 252.0938. _5-Bromo-2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3s**) [63]. A yield of 0.353 g (87%), 6.5 h, yellow solid. Mp. = 253-254 \({}^{\circ}\)C (DMAC/H\({}_{2}\)O, lit. [63] 248-250 \({}^{\circ}\)C). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 12.54 (br.s, 1H), 11.62 (s, 1H), 8.50-8.45 (m, 1H), 8.15 (d, \(J\) = 2.8 Hz, 1H), 7.70 (br.s, 1H), 7.53-7.48 (m, 2H), and 7.28-7.18 (m, 3H) ppm; \({}^{13}\)C[\({}^{1}\)H] NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 150.7, 136.4, 126.5, 125.0, 123.7, 122.2, 121.2, 120.3, 113.1 (br.s), 111.8, and 106.0 ppm. _2-(1H-indol-3-yl)-5,6-dimethyl-1H-benzo[d]imidazole_ (**3t**). A yield of 0.309 g (91%), 7 h, light-beige solid. Mp. = 212-213 \({}^{\circ}\)C, decomposition (DMAC/H\({}_{2}\)O). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 12.33 (br.s, 1H), 8.42 (d, \(J\) = 3.2 Hz, 1H), 8.24-8.19 (m, 1H), 7.67-7.63 (m, 1H), 7.52 (s, 2H), 7.38-7.34 (m, 2H), and 2.40 (s, 6H) ppm; \({}^{13}\)C[\({}^{1}\)H] NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 145.3, 136.6, 134.1, 131.1, 130.0, 123.4, 123.3, 121.6, 119.4, 113.0, 112.9, 99.3, and 19.8 ppm. HRMS (ESI) calcd for C\({}_{17}\)H\({}_{16}\)N\({}_{3}\) [M+H]\({}^{+}\) 262.1339; found 262.1338. _Mixture of 2-(1H-indol-3-yl)-5-trifluoromethylomethyl-1H-benzo[d]imidazole and 2-(1H-indol-3-yl)-6-(trifluoromethylomethyl)-1H-benzo[d]imidazole_ (**3u**) (ratio of isomers 1:1) isolated as a solvate with DMAC (1:1 DMAC). A yield of 0.203 g (52%), 7 h, white solid. Mp. = 52-60 \({}^{\circ}\)C (petroleum ether/EtOAc). \({}^{1}\)H NMR (400 MHz, DMSO-d\({}_{6}\)) \(\delta\) = 12.79-12.78 (m, 2H), 11.70-11.68 (m, 2H), 8.52-8.50 (m, 2H), 8.22-8.20 (m, 2H), 7.95 (br.s, 1H), 7.80-7.75 (m, 2H), 7.65 (d, \(J\) = 8.0 Hz, 1H), 7.54-7.51 (m, 2H), 7.47-7.45 (m, 2H), and 7.26-7.20 (m, 4H) ppm; \({}^{13}\)C[\({}^{1}\)H] NMR (100 MHz, DMSO-d\({}_{6}\)) \(\delta\) = 152.4, 151.9, 146.8 (q, \(J_{\rm CF}\) = 1.0 Hz), 143.8, 136.7 (br.s), 136.5, 133.7, 127.0, 126.7 (q, \(J_{\rm CF}\) = 32.0 Hz), 126.8, 126.7 (q, \(J_{\rm CF}\) = 30.4 Hz), 122.5 (q, \(J_{\rm CF}\) = 270.0 Hz), 126.3, 125.1, 122.3, 121.2, 120.4, 118.4, 118.0 (q, \(J_{\rm CF}\) = 4.6 Hz), 117.6 (q, \(J_{\rm CF}\) = 4.2 Hz), 114.7 (q, \(J_{\rm CF}\) = 4.2 Hz), 111.9, 110.8, 107.4 (q, \(J_{\rm CF}\) = 4.8 Hz), and 105.9 ppm. HRMS (ESI) calcd C\({}_{16}\)H\({}_{11}\)F\({}_{3}\)N\({}_{3}\) [M+H]\({}^{+}\) 302.0900; found 302.0908. _2-(1H-indol-3-yl)-5-methoxy-1H-benzo[d]imidazole_ isolated as a solvate with DMAC (1:0.3 DMAC) (**3v**). A yield of 0.192 g (51%), 6 h, yellow solid. Mp. = 63-65 \({}^{\circ}\)C (DMAC/H\({}_{2}\)O). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 12.21 (brs, 1H), 11.52 (s, 1H), 8.51-8.49 (m, 1H), 8.08 (d, \(J\) = 2.4 Hz, 1H), 7.50-7.43 (m, 2H), 7.23-7.16 (m, 2H), 7.07 (brs, 1H), 6.78 (dd, \(J\) = 8.8, 2.0 Hz, 1H), and 3.81 (s, 3H) ppm; \({}^{13}\)C[\({}^{1}\)H] NMR (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 155.2, 136.4, 125.5, 125.1, 122.0, 121.3, 120.0, 111.7, 109.9 (brs), 106.8, and 55.4 ppm. HRMS (ESI) calcd for C\({}_{16}\)H\({}_{14}\)N\({}_{3}\)O [M+H]\({}^{+}\) 264.1131; found 264.1128. _2-(1H-indol-3-yl)-5-methyl-1H-benzo[d]imidazole_ (**3w**) [64]. A yield of 0.292 g (91%), 8.5 h, light beige solid. Mp. = 253-255 \({}^{\circ}\)C (EOH, lit. [64] 252-254 \({}^{\circ}\)C). \({}^{1}\)H NMR (400 MHz, DMSO-\(d_{6}\)) \(\delta\) = 12.03 (br.s, 1H), 8.37-8.34 (m, 1H), 8.32 (d, \(J\) = 2.8 Hz, 1H), 7.61-7.55 (m, 2H), 7.47 (s, 1H), 7.33-7.27 (m, 2H), 7.17 (d, \(J\) = 8.0 Hz, 1H), and 2.48 (s, 3H) ppm; \({}^{13}\)C[\({}^{1}\)H] NMR (100 MHz, DMSO-\(d_{6}\)) (100 MHz, DMSO-\(d_{6}\)) \(\delta\) = 147.3, 136.5, 134.9 (br.s), 133.2 (br.s), 132.7, 128.9, 124.5, 124.1, 122.8, 121.0, 120.2, 113.4, 113.1, 112.4, 102.5, and 21.1 ppm. _5,6-Dichloro-2-(1H-indol-3-yl)-1H-benzo[d]imidazole_ (**3x**). A yield of 0.365 g (93%), 6 h, gray solid. Mp. = 282 \({}^{\circ}\)C,122.1, 121.9, 121.4, 121.3, 120.1, 120.0, 119.8, 113.8, 113.7, 111.7, 111.6, 110.5, 110.4, 107.2, 106.8, and 106.7 ppm.