Aryl amine polymer

A semiconductive polymer comprising a first repeat unit in the polymer backbone comprising general formula 1: where a=1 or 2; b=0 or 1; and c=0, 1 or 2, provided that when c=0 then b=0; Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 each independently represent an aryl or heteroaryl ring or a fused derivative thereof; characterized in that at least one of Ar1, Ar2, Ar4, and Ar5 is non-conjugating; and provided that (a) when a=1, Ar1 is not linked to Ar2 by a direct bond, (b) when b=1 and c=1, Ar4 is not linked to Ar5 by a direct bond, (c) when b=0 and c=1, Ar2 is not linked to Ar5 by a direct bond, (d) when a=2, the Ar1 groups are not linked by a single bond, and (e) when c=2, the Ar5 groups are not linked by a single bond.