Ethyl vanillin (IUPAC: 3‑ethoxy‑4‑hydroxybenzaldehyde; CAS No. 121‑32‑4) is a white to off-white crystalline powder with a sweet vanilla aroma, around 2–4 times stronger than vanillin. Its formula is C₉H₁₀O₃ with a molecular weight of 166.17 g/mol. It melts at 74–78 °C, boils at 285–295 °C, and is slightly soluble in water but readily soluble in ethanol and ether. With ≥ 95% purity, it's widely used in flavorings, fragrances, and pharmaceuticals.