Open innovation paradigm considers that, in order to advance technologies and markets, firms can and should leverage internal and external knowledge, ideas, expertise, and paths to market. Open innovation being an emerging area of study, the current body of literature is not extensive enough for posing causal questions. Two in-depth case studies at SAP Co-Innovation Lab and IBM India Research Lab were conducted in this research to explore the operationalization aspects of open innovation principles in Information Technology projects. These cases were used to explain how firms identify, assimilate, and integrate external knowledge. As an output of this study, a model was developed to explain the organizational rationale to collaborate, partner selection process, and execution aspects of open innovation projects.