Fig. 1. (Color online) (a) Chemical structures for TAPA, TTDA, and COF_TAPA-TTDA. (b) Schematic for the electrochromic phenomenon of oriented COF_TAPA-TTDA thin film. Reprinted with permission^[12], Copyright 2019, American Chemical Society. (c) The preparation of COF_TAPA-TFPA nanofibers. Reprinted with permission^[14], Copyright 2020, Elsevier.

Fig. 2. (Color online) (a) Schematic for the redox process of COF_TAPA-TFPA nanofibers. Reprinted with permission^[14], Copyright 2020, Elsevier. (b) Synthetic route for COF_TPBD-BTDD. Reprinted with permission^[15], Copyright 2020, Springer Nature.

Fig. 3. (Color online) (a) Color switching of COF_TPBD-BTDD device. Reprinted with permission^[15], Copyright 2020, Springer Nature. (b) Chemical structures for TPDA, PDA, and COF_TPDA-PDA. (c) The three-state electrochromic behavior of COF_TPDA-PDA thin film. Reprinted with permission^[16], Copyright 2021, Wiley.

Table 1. Electrochromic properties of COF-based EC materials.