Compounds of the formulae (I) or (II) wherein X is A is O, S, NR5 or CR16R17; R1 is for example hydrogen or C1-C20alkyl R2 is for example hydrogen, C1-C20alkyl or C6-C20aryl R5 for example is C1-C20alkyl; R7, R8, R9, R10 and R11 for example independently of each other are hydrogen. C1-C20alkyl, halogen, CN or NO2; Ar1 is for example unsubstituted or substituted C6-C20aryl, C3-C20heteroaryl, C6-C20aroyl, C3-C20heteroarylcarbonyl or or Ar1 is Ar2 is for example phenylene, all of which are unsubstituted or substituted M is for example unsubstituted or substituted C1-C20alkylene Y is a direct bond, O, S, NR5 or CO; Z1 is for example O or S; Z2 is a direct bond, O, S or NR5; and Q is CO or a direct bond.