While extant scholarship has yielded a nuanced picture of how people have used ICTs during political activism, less is known about why activists have appropriated and maneuvered some technologies but not others for political action, against different contexts. What, especially, would be the reasoning behind activists’ decision on use or nonuse of a specific technology? To answer the question, this study advances a relational approach that dissects the relevant, yet rarely addressed, link between Gibsonian affordance, understood as action possibilities, of technology, which underpins its subsequent (non)use as a ‘repertoire of contention,’ namely the practice and performance of political activism. Along with the relational approach, this study presents an empirical and comparative perspective to examine how and why Hongkongers selected, coordinated, or discarded various ICTs for activism in the 2014 Umbrella Movement and the Anti-Extradition Law Amendment Bill movement. The findings reveal that activists hold diverse understandings and interpretations of technology and thereby strategically or tactically turn some technologies or functions of a certain technology into their contentious usage on the basis of affordances. The relational framework helps disclose specific dynamics of affordances behind repertoire selection and constraint.