Palladium is a key element in fuel cells, electronic industries, and organic catalysis. At the same time, chromium is essential in leather, electroplating, and metallurgical industries. However, their unpremeditated leakage into aquatic systems has caused human health and environmental apprehensions. Herein, we reported the development of an sp2 carbon‐conjugated fluorescent covalent organic framework with a guanidine moiety (sp2c‐gCOF) that showed excellent thermal and chemical stability. The sp2c‐gCOF showed effective sensing, capture, and recovery/removal of Pd(II) and Cr(VI) ions, which could be due to the highly accessible pore walls decorated with guanidine moieties. The fluorescent sp2c‐gCOF showed higher selectivity for Pd(II) and Cr(VI) ions, with an ultra‐low detection limit of 2.7 and 3.2 nM, respectively. The analysis of the adsorption properties with a pseudo‐second‐order kinetic model showed that sp2c‐gCOF could successfully and selectively remove both Pd(II) and Cr(VI) ions from aqueous solutions. The polymer also showed excellent capture efficacy even after seven consecutive adsorption‐desorption cycles. Hence, this study reveals the potential of fluorescent sp2c‐gCOF for detecting, removing, and recovering valuable metals and hazardous ions from wastewater, which would be useful for economic benefit, environmental safety, human health, and sustainability. The post‐synthetic modification of sp2c‐COF with suitable functionalities could also be useful for sensing and extracting other water pollutants and valuable materials from an aqueous system.

The increasing resistance of bacteria to commercially available antibiotics threatens patient safety in healthcare settings. Perturbation of ion homeostasis has emerged as a potential therapeutic strategy to fight against antibacterial resistance and other channelopathies. This study reports the development of 8-aminoquinoline (QN) derivatives and their transmembrane Zn2+ transport activities. Our findings showed that a potent QN-based Zn2+ transporter exhibits promising antibacterial properties against Gram-positive bacteria with reduced hemolytic activity and cytotoxicity to mammalian cells. Furthermore, this combination showed excellent in vivo efficacy against Staphylococcus aureus. Interestingly, this combination prevented bacterial resistance and restored susceptibility of gentamicin and methicillin-resistant S. aureus to commercially available β-lactam and other antibiotics that had lost their activity against the drug-resistant bacterial strain. Our findings suggest that the transmembrane transport of Zn2+ by QN derivatives could be a promising strategy to combat bacterial infections and restore the activity of other antibiotics.