[摘要]:A pi-conjugated electrochromic polymer (ECP) with alkyl ester side-chains is synthesized and subsequently defunctionalized to yield a polyionic salt readily soluble in water and further spray-processable from water. Upon neutralization, the defunctionalized polymer backbone recovers its electrochromic properties. The ability to print- or spray-process pi-conjugated ECPs from aqueous media offers a sustainable alternative to traditional organic solvent-processing methods and could impact the development of non-emissive flexible display technologies.