 Covalent organic frameworks, COFs, represent an emerging class of organic photocatalysts, but it remains challenging to gain insight into photocatalytic active sites and reaction mechanisms. Herein, the authors construct a family of iso-articular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local poor characteristics of the COFs modulated using different linkers. This article was authored by Zhang Shanshen, Jimmy Wang, Meng Jiehao, and others.