2-Quinolone is an organic compound related structurally to quinoline.

It is the majority tautomer in equilibrium with 2-quinolinol.

The compound can be classified as a cyclic amide, and as such is used as an isostere for peptides and other pharmaceutically inspired targets.

[3] The isomer 4-quinolone is the parent of a large class of antibiotics called quinolone antibiotics.

A prominent example is ciprofloxacin, a broad spectrum antibiotic commonly used for treatment of various infections such as urinary tract infections (UTIs), typhoid, meningitis, gonorrhoea, syphilis,[4] and skin infections.