Idiosyncratic deals (‘i‐deals’, which include customized work arrangements and resources) have been found to motivate R&D employees. However, less effort has been devoted to exploring the uncertain consequences of receiving i‐deals at work, such as violation of leaders’ orders to stop working on certain new ideas (creative deviance). Drawing on the uniqueness theory, we hypothesize that receiving i‐deals indirectly relates to the creative deviance of R&D employee through psychological entitlement. Furthermore, we propose that an R&D employee’s conformity value weakens this indirect relationship. Using a multisource time‐lagged survey study (Study 1) and an experimental scenario study (Study 2), we found consistent evidence that psychological entitlement mediates the indirect relationship between i‐deals and employee creative deviance, and this relationship is contingent on the conformity value of the employee. Our research provides new insights for both scholars and practitioners in R&D management to understand the possible consequences of using i‐deals to motivate R&D employees.