We introduce the first chemical construction set in chemistry (besides natural proteins, starches, sugars, etc.), the metal-organic framework. A DuPont employee, E.A. Tomic, invented this type of molecule in the 1960s, but it took until Omar Yaghi's research in 1990s until chemists realized the value of metal-organic frameworks. We discuss the experiments and results leading up to Yaghi's work, what these frameworks are, their value in science and industry, and their nearly infinite flexibility to create porous materials.Support the show Support my podcast at https://www.patreon.com/thehistoryofchemistry Tell me how your life relates to chemistry! E-mail me at steve@historyofchem.com Get my book, O Mg! How Chemistry Came to Be, from World Scientific Publishing, https://www.worldscientific.com/worldscibooks/10.1142/12670#t=aboutBook