This course introduces participants to light induced reaction. Furthermore, it covers the properties of common as well as novel (functional) photoresists, detailing their design, synthesis and application. Participants will learn about the main chemical processes and materials involved in different 3D printing techniques using light as well as to gain insights into the possibilities and challenges. Here and here you can find short introductions to the module by Cluster Young Scientists Clara Vázquez-Martel and Pascal Kiefer.