Polymethyl substituted [2.2]metaparacyclophanes were synthesized via the corresponding 2,11-dithia [3.3]metaparacyclophanes. Photooxygenation reaction of 4,5,6,12,13,15,16-heptamethyl[2.2]metaparacyclophane using a high pressure mercury lamp led to the mono-endoperoxidation of only the para benzene ring; this was attributed to the much larger degree of deformation of the para-benzene ring than of the meta-benzene