Optimizing the synthesis of imine-linked covalent organic frameworks for high surface areas

Covalent organic frameworks (COFs) continue to attract attention for their structural precision and tunable porosity, yet reliably achieving high surface area remains difficult. In this work, we clarify how common reaction parameters actually influence the formation of imine‑linked COFs. Using COF‑SDU1 as model system, we show that a straightforward open-reflux synthesis, one that does not require degassing or specialized equipment, can produce materials with a high specific surface area of 2163 m 2 g −1 , nearly twice the highest value previously reported for comparable template-free COFs (1125 m 2 g −1 ). A more elaborate, multi-step procedure yields only a slight improvement (2241 m 2 g −1 ), demonstrating that the increased complexity and energy use offer little practical benefit. By directly comparing these approaches, we identify which synthetic choices truly matter and which can be safely simplified. These insights provide experimentally grounded guidance for the rational and reproducible preparation of high surface area imine-linked COFs.