Monomers 3a-c were prepared according to reported procedures with modifications (Fig. ). The SNAr reactions of dichlorodicyanopyrazine 1 with corresponding alkyl-and arylamines were carried out to produce monoaminated products 2a-c. Dimerization of 2a-c using triethylamine was performed in refluxing N,N-dimethylformamide (DMF) to obtain desired monomers 3a-c. The monomers 3a-c were identified by 1 H and 13 C NMR spectroscopy, mass spectrometry, and X-ray crystallography (see SI for details). With three monomers in hand, we investigated the polymerization reactions. As shown in Fig. , polymer 4a was synthesized by the cyclotetramerization of the dicyanopyrazine moieties of monomer 3a in the presence of anhydrous zinc chloride (0.5 equiv.), n-pentanol, and a catalytic amount of triethylamine in N,N-dimethylacetamide (DMAc). The mixture was heated without stirring and the solution turned dark green as the reaction progressed. Polymer 4a was obtained as an insoluble black solid and thoroughly washed with organic solvent and water. The use of diphenyl ether instead of DMAc as solvent afforded a brittle solid. In the reaction conditions using 1,8-diazabicyclo [5.4.0]-7-undecene as a base, no insoluble solid product was obtained. The optimized procedure using DMAc and triethylamine was also applied to 3b and 3c, and as a result, an insoluble black solid (polymer 4b) was obtained from 3b whereas no solid was formed from 3c. These results indicate that 3a and 3b were polymerized to form highly crosslinked polymers. As described in Fig. , the oligomers of 3a cannot form a planar 2D sheet, suggesting the formation of 3D structures. On the other hand, no polymer was obtained from 3c. Considering that the electronic effects of the mesityl and 3,5-di-tert-butylphenyl groups are comparable, the size of the substituent causes a significant difference in the reactivity of polymerization. The formation of TPyzPz structure was confirmed by the cyclotetramerization of 2,3-dicyanopyrazine under the reaction conditions using zinc chloride, n-pentanol and triethylamine in DMAc to obtain compound 5 in 70% isolated yield (Fig. ). To confirm the polymer structures in detail, a series of analyses were performed including Fourier transform infrared (FT-IR) spectroscopy, solid-state C nuclear magnetic resonance (NMR) spectroscopy, energy dispersive spectroscopy (EDS), and Powder X-ray diffraction (PXRD) measurement. FT-IR measurements of 4a, 4b and their monomers (3a, 3b) were performed in air using an attenuated total reflectance method. Because the C≡N stretching peak at about 2230 cm -1 observed in the FT-IR spectra of monomers 3a and 3b disappeared in those of polymers 4a and 4b, it is inferred that the cyano groups were consumed (Fig. ). Solid-state 13 C NMR spectra of 4a and 4b using the cross polarization magic angle spinning with total suppression of sidebands (CP-MAS TOSS) method are shown in Fig. and, respectively. In the spectrum of 4a, aliphatic and aromatic signals derived from mesityl groups and TPyzPz moieties were observed. Signals attributed to DMAc were also observed at 160-170 ppm and 25-40 ppm. The spectrum of 4b shows the signals corresponding to 1-ethylpropyl, TPyzPz, and DMAc. For 4b, a small signal at 115 ppm was observed, which could be unreacted cyano groups. The EDS of 4a and 4b were performed using a Schottky emission scanning electron microscope. As shown in Fig. and S12, C, N, and Zn elements are distributed throughout the surface of the solids. PXRD results of 4a and 4b supported the formation of partially ordered polymers (See SI for details). Thermogravimetric analysis was performed to investigate the thermal stability of polymers 4a and 4b. Before the measurement, polymers were soaked in diethyl ether and dried under vacuum. The weight loss derived from decomposition of 4b was observed at around 300 °C, whereas no decomposition of 4a was observed up to 500 °C (Fig. ). These differences in thermal stability are probably due to the 2D and 3D network structures.