Abstract 1,2-Diphenylcyclobutene (7) was reacted with dibromo- and dichlorocarbene, both generated via three different methods. 1,3-Diphenyl-2-halocyclopenta-1,3-dienes 12 were isolated which result from addition of the dihalocarbenes to the cyclobutene double bond of 7. A cationic cyclopropyl-allyl rearrangement (CCA) in gem-dihalobicyclopentanes 8 leads to 2,3-dihalocyclopentenes 9, which under the reaction conditions are dehydrohalogenated to 12. A second carbene addition and rearrangement afford aromatic compounds 11 and 16.