Urban Living Labs (ULLs) operate in dynamic environments, often facing challenges in assessing social impacts due to the complexity and diversity of urban contexts. Overall, this research-in-progress paper underscores the importance of integrating qualitative methods to complement traditional assessments, ensuring that the social dimensions of urban innovation are adequately addressed. Specifically, it explores the application of a design ethnographic approach to staging and assessing co-creation processes in ULLs. It details the implementation of this methodology in the Horizon Europe GREEN-LOG project, which aims to develop sustainable urban and periurban delivery solutions through a series of ULLs across Europe. The authors argue that design ethnography, with its emphasis on participatory research and deep engagement with stakeholders, provides a richer, more holistic framework for process-oriented assessment of social impacts. This approach involves evaluators actively participating in co-creation from the outset, fostering iterative feedback loops that refine both the ULLs processes and future interventions.