Neocuproine (CAS No. 1129-37-1; Chemical Formula: C₁₄H₁₂N₂) is a heterocyclic aromatic compound known as 2,9-dimethyl-1,10-phenanthroline. It appears as a pale yellow crystalline solid and is widely used as a selective chelating agent for copper(I) ions. It is valuable in coordination chemistry, analytical assays, and spectrophotometric copper detection.