Methylcyclopentane is an organic compound with the chemical formula CH₃C₅H₉. It is a colourless, flammable liquid with a faint odor. It is a component of the naphthene fraction of petroleum. It usually is obtained as a mixture with cyclohexane. It is mainly converted in naphthene reformers to benzene.. Methylcyclopentane is not perfectly planar and can pucker to alleviate stress in its structure.