This article describes, and then applies a newly developed framework for classroom citizenship as an entry point into addressing social justice issues in urban science classrooms. The author provides in-depth descriptions of cogenerative dialogues, coteaching, and cosmopolitanism (3Cs), and presents this triad of tools as an approach to research/practice that addresses full participation of youth in an urban physics classroom. By describing the 3Cs, in an urban classroom, the author presents under-discussed issues that inhibit urban youth from fully participating in urban science classrooms, as an inhibitor to social justice within the classroom. (Contains 2 figures.)