Self-assembled monolayers (SAMs) formed by the adsorption of cyclohexanethiols (CHTs) containing an aliphatic ring on Au(111) from a 1 mM ethanol solution were investigated by scanning tunneling microscopy (STM). STM observation shows that the spontaneous adsorption of CHT on Au(111) leads to long-range two-dimensional ordered SAMs. Moreover, molecularly resolved STM imaging clearly reveals that CHT SAMs have an oblique unit cell containing two different molecular features, which can be described as a (5 x 2 root10)R48degrees superstructure. The formation of such a unique superstructure is ascribed to the presence of a flexible aliphatic ring in the molecular backbone of CHT molecules, and it is expected that CHT SAMs on Au(111) are composed of two energetically stable conformers, that is, the equatorial and axial chair conformers.