In this article, we study polarization within civil society. While earlier research on civil society has shown that civil society organizations can be divisive, research on polarization has only paid scant attention to the role of civil society. We bring these two aspects of the literature together to develop a framework for analyzing social capital in a polarized context. The framework helps identify practices that organizations may engage in when shaping social capital and working with others: facilitating the flow of information; providing credentials for actors; influencing agents; and reinforcing identity and recognition. Importantly, while originally developed for a fundamentally positive analysis of the mechanics of social capital, this framework includes inverted practices. In our analysis, we observe a bifurcation of actions depending on what role they play in the polarization dynamic – integrating relations within the poles or separating relations between the poles. In this sense, social capital contributes to intensified polarization. Empirically, the article is based on a dataset of 30 interviews with 24 policy-oriented civil society organizations (CSOs), here termed think tanks, in Poland.