*4.2. Reaction of* **1** *with Cu and NEt4Cl in MeCN*

A suspension of powdered copper (0.57 g, 9.0 mmol) and NEt4Cl (1.58 g, 9.5 mmol) in acetonitrile (30 mL) was heated to 90 ◦C. A solution of **1** (1.13 g, 5.9 mmol) in MeCN (19 mL) was added to the boiling mixture within one hour. After cooling down to room temperature and filtering, the solvent was removed in vacuo. A brown powder was obtained (2.18 g). <sup>1</sup>H- and <sup>13</sup>C{1H}-NMR spectra (Figures S1 and S2) suggested the presence of two compounds: **A** (=**3**) and **B** (=**5**).

Compound **3**: <sup>1</sup>H NMR (400 MHz, DMSO-d<sup>6</sup> ): *δ*= 6.93 (s, C5H), 3.19 (q, NCH2), 1.15 (tt, CH3). <sup>13</sup>C-NMR (101 MHz, DMSO-d<sup>6</sup> ): *δ* = 123.9 (CH), 116.0, 114.8 (2 × CN), 99.4, 96.3 (2 × CCN), 51.3 (t, NCH2), 7.0 (s, CH3). MS: FAB(+): *m/z* = 130.2 (NEt<sup>4</sup> + ); FAB(−): *m/z* = 165.3 ([C9HN<sup>4</sup> −]).

Compound **5**: <sup>1</sup>H NMR (400 MHz, DMSO-d<sup>6</sup> ): *δ*= 3.19 (q, NCH2), 1.15 (tt, CH3). <sup>13</sup>C-NMR (101 MHz, DMSO-d<sup>6</sup> ): *δ* = 127.5 (CH), 115.1, 114.5 (2 × CN), 99.4, 96.3 (2 × CCN), 51.3 (t, NCH2), 7.0 (s, CH3). MS: FAB(+): *m/z* = 130.2 (NEt<sup>4</sup> + ); FAB(−): *m/z* = 164.2 ([C18N<sup>8</sup> <sup>2</sup>−]).

### *4.3. Reaction of* **1** *with NEt4Br in MeCN*

A solution of **1** (3.00 g, 15.6 mmol) and NEt4Br (10.10 g, 48.1 mmol) in MeCN (160 mL) was heated at 50 ◦C for 30 min. Then, the solvent was evaporated in vacuo, and water (150 mL) was added and the resulting suspension was filtered. The residue on the filter was washed with water (50 mL) and dried in vacuo. A brown powder was obtained (3.06 g). <sup>1</sup>Hand <sup>13</sup>C{1H}-NMR spectra (Figures S3 and S4) showed the formation of three compounds: **A** (=**3**), **B** (=**5**) and **C** (=**2b**).

Compound **2b**: <sup>13</sup>C-NMR (101 MHz, DMSO-d<sup>6</sup> ): *δ* = 114.9, 114.0 (2 × CN), 107.2 (CBr), 100.0, 98.4 (2 × CCN), 51.3 (t, NCH2), 7.0 (s, CH3). MS: FAB(+): *m/z* = 130.2 (NEt<sup>4</sup> + ); FAB(−): *m/z* = 243.1/ 245.1 ([C9BrN<sup>4</sup> −])
