(Vapor + liquid) equilibrium of scent components, coumarin (1-benzopyran-2-one, CAS Registry No. 91-64-5) and vanillin (4-hydroxy-3-methoxybenzaldehyde, CAS Registry No. 121-33-5), in alcohols, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure in the dilute composition range of solid components with a recirculation still. Equilibrium compositions were determined with an ultraviolet spectrometer. The activity coefficients of coumarin at infinite dilution in alcohol were almost unity. The activity coefficients at infinite dilution of vanillin in alcohol were less than unity.