This article reviews the research field of poly(1,2,4-triazolium)s as a rising subclass of poly(ionic liquid)s. In comparison to previously studied polyimidazoliums and poly(1,2,3-triazolium)s, we highlight the unique structural features associated with the hydrogen bonds, the lone-pair interactions on the nitrogen atom at ring position 4 (N4) and the capacity to form polycarbenes. Though the chemical structures and the synthetic routes are alike, these features allow poly(1,2,4-triazolium)s to be distinct from other groups of poly(ionic liquid)s in terms of physical and chemical properties, supramolecular chemistry and applications. The challenges in the further development of poly(1,2,4-triazolium)s are discussed, including the scalability in synthesis and in-depth study of their properties for cutting-edge applications.