In an industrial symbiosis initiative (IS-I), an initiating actor faced with a situation aims to enroll other actors in a collective action, or response, to address the situation. The rational myth theory embeds this “situation-response” pair. This paper explores the relevance of rational myth, along with that of plausible promise, to understand the emergence and development of IS-Is. We adapt the definition of these two concepts to IS and illustrate how they take shape with real case studies, by conducting the qualitative analysis of 14 French IS-Is. We demonstrate the potential of this framework to shed new light on IS-Is, and address a new range of questions for the dynamic analysis of initiatives. This paves the way to study the role of plausible promises in the initiation and development of IS-Is, and the design of discourses that enhance initiatives in situations of high potential of synergy.