Luminol is a chemical compound that exhibits chemiluminescence, which means it emits light when mixed with an appropriate oxidizing agent. It is a white-to-pale-yellow crystalline solid that is soluble in most polar organic solvents but insoluble in water. Luminol is synthesized in a two-step process, beginning with 3-nitrophthalic acid. First, hydrazine (N2H4) is heated with the 3-nitrophthalic acid in a high-boiling solvent such as triethylene glycol and glycerol. An acyl substitution condensation reaction occurs, with loss of water, forming 3-nitrophthalhydrazide. Reduction of the nitro group to an amino group with sodium dithionite (Na2S2O4), via a transient hydroxylamine intermediate, produces luminol.

Luminol is used in forensic science to detect bloodstains, as it is highly sensitive to blood and can be activated by the iron in hemoglobin. When sprayed on a suspected area, luminol reacts with the iron in hemoglobin to produce a blue glow, which allows for an interpretation of bloodstain patterns. Luminol is also used in chemistry demonstrations to produce a blue glow, similar to the reactions that fireflies use to emit light.

In summary, luminol is a chemical compound that emits light when mixed with an appropriate oxidizing agent. It is used in forensic science to detect bloodstains and in chemistry demonstrations to produce a blue glow.