This study explores the role of the think tank as an intermediary organization in the open innovation system. Think tank has contributed to the policy process as a mediator between government and public and as a symbolic entity of intellectual innovation to produce knowledge to the public. As the innovation system matures, one of the major challenges in research and practice is the openness and collaboration in the science, technology, and innovation system. While previous literature highlighted the think tank as the knowledge arbitrager transforming ideas into policy issues, few studies address the research questions: Is the conventional role of the think tank still persistent in the open innovation system? What are the demanding roles? This paper tackles these questions by reviewing the current role of the South Korean think tank in the science & technology sector. Based on the open innovation framework, we suggest that think tanks need to play a bigger role as policy entrepreneurs, crossing policy borders and interacting with other partners