 Micro-reactor technology and flow chemistry could play an important role in the development of green and sustainable synthetic processes. In this review, some recent relevant examples in the field of flash chemistry, catalysis, hazardous chemistry and continuous flow processing are described. Selected examples highlight the role that flow chemistry could play in the near future for a sustainable development. This article was authored by Flavio Finnelli, Giovanna Parisi, Leonardo DiGenerro, and others.