Photochemical dimerization of acenaphthylene in surfactant-intercalated graphite oxide (GO) is discussed. Colloidal solution of GO and an aqueous solution of myristyl-trimethylammonium bromide are used to prepare surfactant-intercalated GO. The results indicate that the sites available between the alkyl chains of surfactant-intercalated GO, which are non-polar and flexible, can be used as a noble reaction medium.