A novel class of organic polymer (OP) with customizable functional groups in the backbone and side-chain was designed and synthesized to remove toxic Hg2+ ions from contaminated water within 30 seconds using a simple spin column technique. The two-step synthetic strategy, which takes only one hour to synthesize a pure polymer from low-cost starting materials, effectuate in use for real-world applications. By changing the backbone and side-chain functional groups, their physical, chemical, thermal, morphological, and porous properties were tuned. The key functional group ‘dithiocarbamate’ was strategically incorporated in the polymeric backbone to remove toxic Hg2+. From the screening of synthesized materials, one candidate was effective in removing 99.9% Hg2+ ions from a wide range of contamination (5-400 ppm) via adsorption. By spin column technique, Hg2+ ions were removed in 30 s. The material was completely recyclable and thus reusable up to three cycles. It was also effective in purifying contaminated real water samples, including lake water and tap water. Taken together, this class of material has the potential to be exploited as an economically friendly candidate for various environmental related problems by tuning the structure as per the prerequisites for the application. © 2023 The Royal Society of Chemistry.