Cultural Third Places (CTPs) are hybrid infrastructures situated at the interface of grassroots initiatives and institutional structures. They foster social interaction, shared governance, and everyday cultural participation, especially in socio-spatially marginalized territories. Building on commons theory and the right to culture, this research examines how CTPs can function as transformative infrastructures for cultural justice, sustainability, and community resilience. The research adopts a transdisciplinary and participatory approach. IT critically investigates the transformative potential of CTPs in contributing to sustainable and inclusive development. It addresses the tensions between their emancipatory ethos and the constraints imposed by unstable funding, institutional instrumentalization, and threats of commodification and gentrification. Although celebrated as spaces of possibility (Oldenburg, 1989; Dellenbaugh, 2015), CTPs remain under-theorized, with a lack of context-sensitive frameworks to assess their multidimensional impacts across cultural, social, economic, environmental, and spatial dimensions (Tomaz et al., 2020; Costa et al., 2022). This study presents a comparative analysis of two Portuguese case studies: Largo Residências (Lisbon) and Estação Cooperativa (Casa Branca). The first illustrates urban tensions between cultural regeneration and gentrification, while the second explores rural revitalization through creative reuse of public heritage. Both demonstrate how CTPs contribute to identity-building, inclusion, and territorial care, albeit through different governance and spatial logics. The findings emphasize that third places, when grounded in commons-based governance and collective cultural rights, can generate value far beyond artistic outputs. They support inclusive participation, ecological awareness, and intergenerational learning, but remain vulnerable to institutional instrumentalization and spatial commodification. Urban and rural comparisons show that sustainability hinges on context-specific alliances, cooperative frameworks, and embedded cultural mediation. This research contributes to the ENCATC discourse by offering grounded insights into the governance, sustainability, and policy implications of cultural third places. It aligns with broader European debates on cultural rights, public space, and participatory infrastructures.

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