Indole, also known as 1-benzo[b]pyrrole, is an aromatic heterocyclic organic compound that has a bicyclic structure (a benzene fused to a pyrrole) with the chemical formula C₈H₇N. It is a colorless solid with a very persistent musty odor.

Coumarin, also known as 2H-1-benzopyran-2-one or 1,2-benzopyrone, is a natural aromatic lactone with the chemical formula C₉H₆O₂. It is a colorless crystalline solid with a bittersweet odor like hay and is used as a fixative in perfumes.

Cyclohexanone is an organic compound with the chemical formula C₆H₁₀O. It is a colorless to pale yellow liquid with an odor similar to that of acetone that is very soluble in most organic solvents.

Cyclohexanol is an organic compound with the chemical formula C₆H₁₂O. It is a colorless, viscous liquid or cristalline solid with a camphor-like odor that is very soluble in most organic solvents.

Piperidine, also known by other names such as hexahydropyridine, pentamethyleneimine, azacyclohexane, cyclopentimine, cypentil, and hexazane, is a secondary cyclic amine with the chemical formula C₅H₁₁N. It is a colorless liquid with a strong, unpleasant odor typical of amines.

Cyclohexylamine, also known as aminocyclohexane, is an aliphatic primary amine with the molecular formula C₆H₁₃N. It is a colorless liquid that is miscible with water and common organic solvents.

Ethylamine, also known as ethanamine, is a primary aliphatic amine with the chemical formula C₂H₅NH₂. It is a flammable gas at room temperature with an ammonia-like odor.