Patent ID: 8043722

Claim:
An optionally substituted oligomer or polymer comprising a repeat unit of formula (I): wherein n is at least 1; each A is a nitrogen atom or optionally substituted phosphorus atom; each Ar 1 is the same or different and independently represents an optionally substituted arylene or heteroarylene; each Ar 3 is the same or different and independently represents an optionally substituted aryl or heteroaryl; Ar 2 represents an optionally substituted arylene or heteroarylene comprising a linking ring to which the two atoms A are both directly linked; and at least one of Ar 2 , and/or either or both of Ar 1 is substituted with at least one substituent and at least a second repeat unit, wherein the second repeat unit is selected from optionally substituted spirobifluorene, indenofluorene or dihydrophenanthrene.