Hydrogen-bonded organic frameworks for constructing multi-functional green sensors

• The design strategies of HOF-based sensors including signal-responsive mechanisms and various signal output modalities are comprehensively summarized. • Detailed discussions of the underlying mechanisms of various signal output modes of HOF sensors are reviewed. • The advantages of HOF sensors as green analytical sensors, particularly in terms of recyclability and renewability are discussed. • The challenges faced by HOF sensors and their future development directions are explored. Hydrogen-bonded organic frameworks (HOFs) are an emerging class of porous crystalline materials which are mainly assembled of discrete organic tectons through hydrogen bonding while with assistance of electrostatic, π-π stacking, van der Waals force etc. Owing to the advantages of mild synthesis conditions, metal-free biocompatibility, excellent recyclability and renewability, HOFs present as ideal candidates to construct sensors for the fast and on-demand detection of target analytes in a green and convenient manner. This review provides a comprehensive overview of the development, building blocks and assembly principles of stable HOFs, especially focusing on the design concepts of HOF sensors in terms of signal responsive strategy and signal output modality. Diverse sensing signal output modes including fluorescence, optoelectronic and resistance are summarized and discussed, underlying the insightful sensing mechanisms. Furthermore, the advantages of HOFs as green sensors, including their recyclability and renewability, are discussed. Finally, the limitations and potential of current HOF-based sensors are addressed, and future perspectives are also outlined.