Cyanoethynylethenes: A Class of Powerful Electron Acceptors for Molecular Scaffolding We thank the ETH Research Council and the Fonds der Chemischen Industrie for their support of this work. Robin Gist is acknowledged for the supply of starting materials.

Extended π-electron acceptors, such as 1, have been constructed by the acetylenic scaffolding of a series of novel cyanoethynylethenes. Electrochemical analysis shows that acceptor strength is a function of π-electron conjugation length, and that a linear correlation exists between the electron affinities (B3LYP, 3-21G) and their first reduction potential.