Bismuth(III) oxide is a compound of bismuth, and a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite, but it is usually obtained as a by-product of the smelting of copper and lead ores. Dibismuth trioxide is commonly used to produce the "Dragon's eggs" effect in fireworks, as a replacement of red lead.

Passive daytime radiative cooling (PDRC) is a zero-energy building cooling method proposed as a solution to reduce air conditioning, lower urban heat island effect, cool human body temperatures in extreme heat, move toward carbon neutrality and control global warming by enhancing terrestrial heat flow to outer space through the installation of thermally-emissive surfaces on Earth that require zero energy consumption or pollution. In contrast to compression-based cooling systems that are prevalently used, consume substantial amounts of energy, have a net heating effect, require ready access to electricity and often require coolants that are ozone-depleting or have a strong greenhouse effect, application of PDRCs may also increase the efficiency of systems benefiting from a better cooling, such like photovoltaic systems, dew collection techniques, and thermoelectric generators.