Abstract Dithiole and cyclopentadiene rings have been introduced into functionalised cyclopropa [b] naphthalenes to provide highly coloured, conjugated and cross-conjugated π- extended derivatives that have varying stability. Cyclopentadienylidene-containing cyclopropanaphthalene 18 and its dithiolylidene analogue 25 are prepared from bromophenylcyclopropanaphthalene 12, and the 1, 1-biscyclopentadienylidene 20 from ...