It is quite difficult to say which ingredient was the first synthetic material to be used in perfumery. The first experimental synthetic materials were narrow fractions of essential oils and isolates, individual materials that were isolated from natural sources. Benzaldehyde, which has a bitter almond odor, is sometimes considered among the first synthetic odorous substances. But much more often this momentous milestone is associated with the substance called Coumarin. Strictly speaking, coumarin is not something entirely artificial.