Polymers comprising at least one unit of formula (1) wherein n is 0 or 1, m and p are independently from each other 0, 1, 2, 3, 4, 5 or 6, provided that the sum of n, m and p is at least 2, and n and p are not 0 at the same time, Ar1 and Ar2 are independently from each other C6-14-arylene or C6-14-aryl, which may be substituted with 1 to 4 substituents independently selected from the group consisting of C1-30-alkyl, C2-30-alkenyl, C2-30-alkynyl, C5-8-cycloalkyl, C6-14-aryl and 5 to 14 membered heteroaryl, and X1, X2 and X3 are independently from each other and at each occurrence O or S, compositions comprising these polymers, and electronic devices comprising a layer formed from the compositions. Preferably, the electronic device is an organic field effect transistor and the layer is the dielectric layer.