The paper presents results of empirical qualitative inductive multi-case study.•
Activity coordination and knowledge integration are studied simultaneously.•
Their interplay defines three main types and three sub-types of project architectures.•
Architectures influence collaboration, resilience and project management.•
Research enhances understanding of inter-organizational R&D projects.
The architects of inter-organizational R&D projects organize collaboration by structuring the activities and the knowledge base of the project. How do these two dimensions interplay and what are the implications on the project execution? The paper aims at developing new perspectives on inter-organizational multi-actor R&D projects using an exploratory inductive multi-case study of projects funded by the European Union’s Research and Innovation Programmes. The projects have been studied simultaneously in terms of activity coordination and knowledge integration as well as the implications of their interplay on collaboration, project resilience and project management. The paper provides empirical evidence about six patterns of project architecture. The workflow-integrated architecture disintegrates the knowledge base, provides a lower collaboration potential and may require high management efforts, while a workflow-decomposed architecture makes project management easy but provides little added value from the inter-organizational setting. Nearly decomposable architectures offer the highest collaboration potential under contingent conditions.