What are Complex Systems and how does their investigation impact the foundations of chemistry?

Humanity in the XXI century is called to confront global challenges rooted in the behavior of Complex Systems. As a result, scientists are increasingly driven to orient both research and education toward the interdisciplinary field of Complexity. Chemists, in particular, are encouraged to contribute to this collective effort, as chemistry stands at the crossroads of human and animal health, the planet’s biological and physical environments, and technological innovation. At the same time, chemists are challenged and enriched in their efforts to comprehend Complex Systems and face global challenges. This work presents the viewpoints of two chemists involved in the study of Complex Systems, articulated through a Questions-and-Answers (Q&A) format. They address seven key questions concerning the nature of Complex Systems and the ways in which their investigation is fostering a revolutionary intellectual event in the marvellous journey of humanity towards the comprehension of natural phenomena. The perspectives that emerge highlight how interdisciplinary research on Complex Systems is reshaping the foundations and expanding the role of chemistry.