4.1.1. Preparation of SiPcCl2 (via Route A)

Reaction was performed analogous to previously reported literature starting with 1 g of commercial diiminoisoindoline [27]. Crude yield 0.76 g (1.2 mmol, 73%). Samples were characterized spectroscopically and compared to references in literature [33]. HR-MS (EI) for C32H16Cl2N8Si [M]<sup>+</sup>: Calcd, 610.0644; Found, 610.0635.

4.1.2. Preparation of 2,3-Dihydro-1H-Isoindole-1,3-Bis(Iminium) Bis(Trifluoromethanesulfonate) [H2DIII][OTf]2 (via Route B)

A solution of lithium bis(trimethylsilyl)amide etherate (4.7 g, 19.5 mmol) in dry toluene (200 mL) was added dropwise to a stirring tolyl solution (150 mL) of phthalonitrile (2.5 g; 19.5 mmol) and subsequently stirred overnight. Hydrochloric acid was bubbled into the mixture for 25 minutes. The resulting green slurry was stirred for 30 min, followed by filtration in vacuo and washed thrice with MeCN to afford the green solid of [H2DIII]Cl2. IR νmax = 3120 (br, w), 2672 (br, m), 2545 (br, m), 2347 (br, w), 1671 (s), 1601 (m), 1527 (m), 1475 (m), 1463 (m), 1353 (m), 1318 (m), 1276 (m), 1179 (m), 1086 (w), 1043 (s), 912 (w), 846 (s), 826 (s, br), 787 (s), 746 (m), 728 (m), 690 (s). This material is essentially insoluble in organic solvents; its identity was determined by metathesis to the more soluble triflate salt by the following procedure: Trimethylsilyl trifluoromthanesulfonate (10.6 mL, 58.5 mmol) was added to a slurry of [H2DIII]Cl2 in dry MeCN (25 mL) and stirred for 1 h. The green slurry was filtered in vacuo and washed thrice with DCE to afford a green solid of [H2DIII][OTf]2. Yield 4.8441 g (10.9 mmol, 56%). 1H-NMR (δ, CD3CN, RT, 300 MHz): 8.36 (m, 2H), 8.11 (m, 2H). 19F-NMR (δ, CD3CN, RT, 300 MHz): −79.20 (s, 6F). IR νmax = 3252 (w), 3109 (w), 2967 (m, br), 1678 (m), 1606 (w), 1478 (w), 1467 (w), 1353 (w), 1300 (m), 1284 (m), 1271 (m), 1236 (m), 1217 (s), 1192 (s), 1167 (s), 1091 (w), 1077 (m), 1033 (s), 1022 (s), 978 (w), 868 (m), 840 (m), 783 (m), 764 (m), 748 (m), 697 (m).

4.1.3. Preparation of Silicon Phthalocyanine Dichloride (via Route B)

A solution of lithium bis(trimethylsilyl)amide etherate (4.7 g, 19.5 mmol) in dry toluene (200 mL) was added dropwise to a stirring solution of phthalonitrile (2.5 g; 19.5 mmol). After 5 h, the reaction mixture was cooled in an ice bath and hydrochloric acid was bubbled into the mixture for 25 min. The

resulting green slurry was stirred for 30 min followed by filtration in vacuo and washed thrice with MeCN. To the filtered solid, dry quinoline (75 mL) and silicon tetrachloride (3.2 mL, 28.1 mmol) were added. The stirring slurry was heated to 180 ◦C for 4 h producing a visible red microcrystalline solid. The solid was filtered and washed with benzene, followed by methanol and acetone, respectively. Crude yield 0.63 g (1.0 mmol, 21%). Samples were characterized spectroscopically and compared to references in literature [33]. HR-MS (EI) for C32H16Cl2N8Si [M]<sup>+</sup>: Calcd, 610.0644; Found, 610.0632.
