Today’s urbanization pressures present complex challenges in sustainable and socio-ecological transitions. Historical planning tools and theories, such as the Open Society concept, offer alternative approaches to regeneration and inclusivity. Critical mapping is a growing method in urban regeneration. However, we observed that this tool has not been sufficiently explored in a comparative fashion. In this paper, we examine the Open Society concept by comparing and contrasting ’t Hool, Eindhoven and Montbau, Barcelona to assess the concept’s continuing relevance for the regeneration of Modernist housing in the twenty-first century. We construct a comparative critical cartography using mixed-methods (mostly qualitative) to highlight interspatial relations on both neighborhoods. This method is a tool that aids us to highlight power-knowledge relations and detect spatial patterns from different fields, to extract site-specific lessons that inform urban regeneration. This research bridges the gap between theory, design and practice providing tools and comparative approaches to promote more transdisciplinary and more holistic approach to space and place. Addressing the complexity of space with a creative and systematic approach should address the relativism of site-specific knowledge and turn it into more generalizable lessons for urban regeneration.