Abstract: Singlet oxygen (¹O₂) is a highly reactive species with strong oxidizing properties, making it valuable in various applications, including photodynamic therapy, organic synthesis, and material science. However, its short lifetime and high reactivity present significant challenges in its practical use. To overcome these challenges, the development of efficient materials for ¹O₂ capture and controlled release has attracted considerable attention. Covalent organic frameworks (COFs), with their unique crystalline structure, high porosity, and exceptional stability, have emerged as ideal candidates for 1O? storage and transfer. In this study, we designed and synthesized a two-dimensional anthracene-based COF (2D An COF), which was further exfoliated into nanosheet (2D An COF-nanosheet) to enhance its performance. Fluorescence spectroscopy analysis demonstrated that the 2D An COF nanosheet exhibited a significantly higher 1O? capture rate compared to the bulk COF, which can be attributed to their more exposed active sites. Both the 2D An COF and its exfoliated nanosheet showed excellent reversibility in ¹O₂ release when exposed to external thermal or light stimuli, with no significant degradation in performance after multiple cycles. The results highlight the potential of 2D COF materials, particularly in nanosheet form, as efficient and stable platforms for 1O? storage and release. This work provides new theoretical insights into the design of ¹O₂-responsive materials and opens new avenues for applications in photodynamic therapy, photocatalysis, and other fields requiring precise control over reactive oxygen species.

Key words: porous material, covalent organic frameworks, nanosheet, anthracene, singlet oxygen capture and release