Increasingly, Design Thinking has influence beyond the confines of traditional design disciplines and expands its’ role in connecting domains and integrating resources. This study focusses on the changing role of design researchers involved in interdisciplinary research projects, following a Research-through-Design (RtD) approach. The research context for this study is a project on designing and evaluating digital solutions in the context of dementia. Based on process research methods this study provides a holistic view on dynamics between actors from different domains and an understanding on the role of design researchers within the complexity of the larger system of an interdisciplinary RtD-collaboration. Findings on organizational-, process- and product level emphasize on three changing roles for design researchers in interdisciplinary RtD: 1) A mediator role, 2) a sensemaking role, and 3) a role in improving processes by applying research artefacts.