Compared with the conventional solvothermal method, which is usually reacted in a sealed glass tube to obtain micrograms-scale COFs in the presence of organic solvent and hinder their practical applications, the melt polymerization strategy avoids most of the disadvantages of the solvothermal method, which is desirable for the large-scale production of materials. Therefore, we attempted to scale up the synthesis of NKCOF-62 using an autoclave by one-pot reaction, and a red cylinder shape (0.51 kg) was easily obtained under the same reaction condition (Figure ). Notably, the BET surface area and crystallinity of the large-scale NKCOF-62 were comparable to that of the equivalent small-scale synthesis (Figure ). These results further demonstrated that NKCOF-62 could be easily scaled up to a large amount depending on the requirement in principle, which addressed the grand challenges of scalable COF synthesis that are inaccessible through traditional solvothermal approaches. Furthermore, the cost of preparing a kilogram of NKCOF-62 is <75$/kg, far below most reported COFs (Table ), which exhibits great potential for industrial production and application. and). The amount of adsorbed gas in activated NKCOF-62 decreased with increasing temperature. Interestingly, the adsorption capacity of NKCOF-62 for C 2 H 2 and C 2 H 6 was higher than that for C 2 H 4 across the entire pressure range tested (0-100 kPa), implying selective adsorption of C 2 H 2 and C 2 H 6 over C 2 H 4 . To evaluate the affinity of C 2 hydrocarbons with NKCOF-62, the coveragedependent isosteric heat of adsorption of (Q st ) for C 2 H 2 , C 2 H 4 and C 2 H 6 was calculated using the virial equation (Figure and Table ). As shown in Figure , the order of Q st values at zero coverage was C 2 H 2 (30.5 kJ/mol) > C 2 H 6 (29.6 kJ/mol) > C 2 H 4 (26.3 kJ/mol), indicating that NKCOF-62 has the strongest affinity for C 2 H 2 , followed by C 2 H 6 and finally C 2 H 4 which was useful in the separation and purification of C 2 H 4 and consistent with the absorption amounts measured from the adsorption isotherms. Notably, the adsorption enthalpies of all three gases were lower than 35 kJ/mol, indicating that NKCOF-62 had a relatively low energy footprint for sorbent regeneration. To further evaluate the separation performance of NKCOF-62, the ideal adsorbed solution theory (IAST) was utilized to calculate the binary gas mixture 1/99 C 2 H 2 /C 2 H 4 and 50/50 C 2 H 6 /C 2 H 4 adsorptive selectivity. As shown in Figure and S23, the predicted selectivity of C 2 H 2 /C 2 H 4 and C 2 H 6 /C 2 H 4 at pressure of 1 bar and 298 K were 1.30 and 1.37, respectively, which was comparable to most reported adsorbents for one-step C 2 H 4 purification from a ternary C 2 H 2 /C 2 H 4 /C 2 H 6 mixtures (e.g., NPU-1, NPU-2, UPC-612 and Azole-Th-1 ), implying the feasibility of using NKCOF-62 to purify C 2 H 4 from C 2 H 2 and C 2 H 6 in practical applications.