Coalitions are one of the most important forms of Social Movement Organizations (SMO). However, the creation of coalitions has not received much attention in the recent growing efforts devoted to create bridges between organizational and social movement theories. Organizational sociology have paid considerable interest to institutional entrepreneurs in social movements, which with their cognitive abilities reframe the logics of a specific field; however - and somehow paradoxically- organizational theory have paid less attention to organizational entrepreneurs in social movements, that is, individuals that create new forms SMO, as webbased coalitions. We try to fill these lacunae in current research of entrepreneurship in social movements studying both the organizational and institutional efforts in the creation of a new web-based coalition in the US environmental movement, namely the Plastic Pollution Coalition. This comparative approach can shed new light to the study of entrepreneurship in social
movements, showing how the dynamics of different kinds of efforts can have different rhythms and paces, and can create ?bottle-necks? in the diffusion of the transformative entrepreneurial action.