Abstract: A variety of polymeric materials were developed as the basis for sequestering and sensing ions in aqueous solution. Polymers were made that can act: as selective ion exchange resins. The selectivity can sometimes be made to approach exclusivity and allow the simultaneous removal and purification of a variety of chemicals. This approach can be used to turn waste streams of hazardous chemicals into resources of valuable materials. In addition, some of the polymers were used to construct ion selective electrodes for sensing ions in aqueous solution. Similar polymers were constructed with complexing monomers that possess chromophores, allowing for the construction of chemically selective optical ion sensors. The result of these studies is a general approach for the construction of selective ion sequestering and sensing polymers