Despite the well-established foundation of polyurethane chemistry in both industry and academia, research continues at a vigorous pace to refi ne synthetic processes and discover new functional materials. Incorporating ionic groups into polymers is a synthetic parameter capable of tailoring polymer properties and enabling emerging technologies. This review focuses on recent effort in the fi eld of ion-containing segmented polyurethane copolymers. Multiple synthetic strategies to incorporate both cationic and anionic sites, including a particular focus on waterborne polyurethane dispersions and green synthetic methods, are examined. Fundamental structure-property relationships based on ionic structure, content, and placement are explored and many applications, including biomedical products and polymer electrolytes for energy devices are discussed.(PEG) or poly(tetramethylene oxide) (PTMO), to the polyurethane reaction. The hydrogen bonding, depicted in Figure 1 , between the urethane carbonyl oxygen and urethane hydrogen, coupled with crystallization, constructs the hard segment (HS) domains, while the functionalized fl exible spacers comprise the soft segments (SSs) in an alternating fashion. The microphase-separated morphology of segmented polyurethanes is the foundation for their versatility, with the ability to further tune materials for a specifi c application with other synthetic parameters such as chemical composition and molecular weight. Yilgör and co-workers, [ 5 ] Yurtsever and co-workers, [ 6 ] and Wilkes and co-workers [ 7 ] extensively studied various model segmented polyurethane systems to further understand the morphology and factors infl uencing morphology on a fundamental structure-property level.Many comprehensive reviews and peer-reviewed journal articles focus on fundamental structure-property relationships of segmented polyurethanes.