Over the past decade, significant progress has been made in the development of ion-imprinting polymers (IIPs) and molecular--imprinted polymers (MIP), driven by the need for highly selective ion recognition and removal in environmental, biomedical, and industrial applications. By creating tailor-made binding sites for specific targets, these materials offer exceptional selectivity, high adsorption capacity, and strong reusability. Recent innovations in functional monomer design, crosslinking strategies, and hybrid material integration have further improved their mechanical stability, chemical resistance, and overall performance in diverse operating environments. Such advancements have positioned IIPs and MIPs as key materials for sustainable water treatment, nutrient recovery, pollutant remediation, sensing, and biomedical applications.

This Special Issue aims to collect high-quality original research articles, communications, and reviews focusing on the design, synthesis, characterization, and performance evaluation of IIPs, MIPs and hydrogels.

Topics of interest include, but are not limited to:
- Rational design of functional monomers, crosslinkers for ion/molecular imprinting
- Preparation of imprinted polymers, polymer composites and imprinted hydrogels
- Polymer structure-recognition property relationships
- Interfacial interaction mechanisms between polymer matrix and target analytes/ions
- Environmental, resource and sensing applications of imprinted polymeric materials
- Green synthesis, recyclability and stability of imprinted polymer materials

Manuscripts centered only on adsorption testing without sufficient discussion of polymer material design and mechanisms are not suitable for this collection.