Compounds having electroluminescent or electron transport properties

A composition comprising a compound of the formula

• R1(CR3═CR4)nAr(CR4═CR3)nR2
• wherein:
• n is 0 or 1;
• Ar represents aryl or heteroaryl having 1-5 aromatic rings which is optionally chain or fused or a combination of chain and fused, which is optionally substituted with alkoxy, fluoro, fluoroalkyl or cyano and which in the case of a 5-membered ring nitrogen heteroatom is optionally N-substituted with aryl or substituted aryl optionally further substituted with alkoxy, fluoro, fluoroalkyl or cyano;
• R1 and R2 independently represent aryl or nitrogen, oxygen or sulphur-containing heteroaryl having two to four fused aromatic rings one of which is optionally a 5-membered and optionally substituted by aryl or heteroaryl having 1-5 chain or fused aromatic rings which is optionally further substituted with alkoxy, fluoro, fluoroalkyl or cyano;
• and
• R3 and R4 independently represent hydrogen, methyl, ethyl or benzyl, and a dopant.