The United Nations named 2022 the International Year of Glass to honour one of the world's most transformative and efficient materials and to emphasise the importance of glass material research. On top of inorganic, metallic, and organic glasses, metal-organic framework (MOF) glass has been recognised as the fourth generation of glass materials, also the very first new generation in the last 50 years. It is fabricated via melt quenching of a small group of metal-organic framework materials, generating a new generation of amorphous, microporous glassy materials. It offers accesses to an array of new composite materials. For example, lead halide perovskite (LHP) semiconductors show exceptional optoelectronic properties. Important barriers for their practical applications, however, lie in their instability to polar solvents, polymorphism, phase segregation and sensitivity to the leaching of toxic metal ions. We recently reported a new type of scalable composites fabricated through liquid phase sintering of LHP crystals / zeolite imidazolate framework (agZIF-62) glass. The glass substrate can accommodate ionic, crystalline LHP particles. Interfacial interactions effectively stabilize the metastable LHP phase, passivate LHP surface defects and impart bright, narrow-band photoluminescence. The microporous ZIF glass provides effective protection for LHPs against immersion in water and organic solvents, alongside mechanical stress and heat. The composites show ultra-stable photoluminescence in water for over 10,000 h. These properties, together with their lead self-sequestration capability, will enable practical applications of LHPs, e.g. in photocatalysis and white light emitting diodes (LEDs).