This tutorial review highlights the representative advances in the new synthetic strategies toward covalent organic frameworks.

Two‐dimensional covalent organic frameworks (2D COFs), an emerging class of crystalline porous polymers, have been recognized as a new platform for efficient solar‐to‐hydrogen energy conversion owing to their pre‐designable structures and tailor‐made functions. Herein, we demonstrate that slight modulation of the chemical structure of a typical photoactive 2D COF (Py‐HTP‐BT‐COF) via chlorination (Py‐ClTP‐BT‐COF) and fluorination (Py‐FTP‐BT‐COF) can lead to dramatically enhanced photocatalytic H2 evolution rates (HER=177.50 μmol h−1 with a high apparent quantum efficiency (AQE) of 8.45 % for Py‐ClTP‐BT‐COF). Halogen modulation at the photoactive benzothiadiazole moiety can efficiently suppress charge recombination and significantly reduce the energy barrier associated with the formation of H intermediate species (H*) on polymer surface. Our findings provide new prospects toward design and synthesis of highly active organic photocatalysts toward solar‐to‐chemical energy conversion.

This review summarizes the latest advances of porous organic polymers (POPs) focusing on their applications in photocatalysis, including photocatalytic chemical transformations, photodetoxification of pollutants from water, and water splitting.

Photocatalytic covalent organic frameworks were facilely constructed via the integration of alternative donor–acceptor units into the 2D extended and crystalline scaffolds, which exhibit excellent photodegradation efficiency toward aqueous Cr(vi).

Two imine-based two-dimensional covalent organic frameworks (2D COFs: TPT-Azine-COF and TPT-TAPB-COF) which exhibit large surface areas and good crystallinity were synthesized from flexible building blocks. Both of them exhibit a prominent adsorption capacity for Rhodamine B (970 mg g–1) and volatile iodine (225 wt %) with good recyclability.