This study aims to understand how civil society organizations (CSOs) perform and influence public arenas. The focus of this paper is the transformative scope of social innovation initiatives promoted by CSOsin two public arenas in Brazil: the fight against electoral corruption and the protection of children and adolescents? rights. The research consisted of three stages: 1) controversy mapping to understand the configuration ofthese public arenas and compare the trajectories of the public problems studied; 2) observation of the ?field of experience? of some CSOs that perform in these arenas; and 3) analysis of ?political grammars? produced in public arenas, connecting them to the performance of the CSOs analysed. The results reveal how social innovation emerges, develops and is disseminated in the public arenas studied and highlights the similarities and differences between the two cases, discussing the practices and role of CSOs in these processes. As conclusions, the study indicates that social innovation initiatives promoted by CSOs are influenced by and have an effect on the ?political culture? in the public arenas. Additionally, this work states that the regime of CSOs? engagement in the public sphere and their performance have consequences in terms of influence on social and political changes. In the cases studied, when CSOs go beyond the logic of coproduction of public services and engage in ?public inquiry? processes, their capacity to inspire social transformation seems to be enhanced.