This issue of Photonics Focus looks at materials that are changing our understanding of photonics. Nanomaterials are increasing the efficiency of solar cells closer to the theoretical limit. Topological materials have promising applications as catalysts, high-temperature superconductors, magnetic storage media, and even qubit generators for quantum computers. AI is finding new light-emitting molecules for OLEDs, which have yet to fully realize their promise of long life and cheap production.