This internship-based thesis examines how the Geneva Environment Network (GEN) has contributed to global sustainable development discourse, with a particular focus on plastic pollution, through its event programming. Drawing on theories of knowledge brokerage and agenda framing, the study asks: How, and to what extent, has GEN’s convening and public curation influenced agenda salience, cross-community alignment, and negotiator preparedness around key policy windows? The research applies longitudinal Contribution Analysis (1999–2025) with embedded Process Tracing. A harmonised event archive was constructed from GEN’s public websites and hubs, UN and UNEP documentation, and independent reporting, coded for themes, partner categories, formats, access artefacts, and proximity to decision moments (UNEA and INC). Mechanism-specific predictions are tested through a focused plastics subcase (2020–2025), including the Geneva Beat Plastic Pollution Dialogues (GBPP), pre-INC briefings, and the Road to Geneva hub. Three principal findings emerge. First, GEN’s programming clusters within ±60 days of major policy windows and is accompanied by curated knowledge artefacts (recordings, presentations, consolidated links), indicating reduced information costs and increased agenda salience. Second, event series consistently combine cross-sectoral partners (trade and standards, chemicals and waste, health, human rights, and missions), supporting coalition-alignment tests around shared lifecycle framings. Third, alignment between GEN’s framings and official negotiation agendas, combined with single-entry knowledge hubs, contributes to negotiator preparedness, while final bargaining outcomes (e.g., the INC-5.2 adjournment) remain outside GEN’s control. Hybrid formats expanded access and observability, although public records limit reliable measurement of representation. The findings suggest that GEN could strengthen its intermediary role by formalising a T–90/T–60/T–15 event cadence around policy windows, systematically tracking cross-community bridges, publishing light-touch inclusion and usability indicators, standardising documentation practices, and coordinating shared metacalendars to reduce venue crowding. For MIHDS peers, the internship produced reusable datasets, codebooks, and templates, and demonstrates a rigorous, ethics-compliant approach to contribution-focused evaluation. Key limitations were reliance on public records and the absence of interviews, pointing to future research using semi-structured interviews and comparative network analysis across governance hubs.