Researchers have proposed an approach to create metal-organic frameworks (MOFs) that are designed to be safe and sustainable. The approach categorises the transformations that these materials undergo, helping to prevent the formation of harmful transformation products. MOFs are composed of metal clusters linked to organic compounds, resulting in porous structures that are useful in various applications, including catalysis, energy storage, water treatment, and sensors. By adopting a safe and sustainable approach in their design, the full potential of MOFs can be realised.