Used primarily as a flavor and fragrance ingredient, nona-2,4-dienal is an unsaturated aldehyde that contributes a powerful green, cucumber-like aroma with violet leaf and slightly fatty nuances. It is commonly employed in perfumery to impart fresh, aldehydic, and green notes to soaps, detergents, and fine fragrances. In flavor formulations, it enhances cucumber, melon, vegetable, and tropical green profiles, particularly in products mimicking fresh produce or herbaceous notes. Due to its high potency and volatility, it is used in very low concentrations to add a natural, vibrant character to food products, beverages, and personal care items without overpowering other ingredients.