A network of think tanks—the ASEAN-Institutes of Strategic and International Studies and their researchers—have played a proactive and sometimes influential role in regional debates on Asian economic integration and security cooperation through informal diplomacy. This paper contributes to the literature on knowledge utilisation, specifically debates on the role of policy research institutes in policy-making. Paying attention to the debates and research on economic and security cooperation which preceded attempts at institutionalisation drives analytical attention to scholars, think tanks and others in the ‘interpretive community’ who were engaged in a long term learning activity to shape domestic and regional agendas and institutionalise discourses of regional cooperation.