Abstract: New 2-(2'-hydroxyphenyl)-benzotriazoles are used for protecting light-sensitive organic materials. They are prepared by diazotization of a 2-nitroaniline, coupling of the resulting diazo compound with a phenol and reduction of the resulting 2-nitroazo compound.

Abstract: The polymeric malonates of the invention have the formula ##SPC1##WhereinR.sub.1 and R.sub.2 are alkyl groups,R.sub.3 is an alkyl or hindered hydroxybenzyl group,A is oxygen or amino group,X is a divalent group such as unsubstituted or substituted alkylene or thioalkylene,Y is hydrogen or a hindered hydroxybenzyl group,Z is hydrogen, hydroxy, alkoxy or thioalkyl group, andn is 2 to 100.These compounds are prepared by reacting esters of malonates with divalent alcohols or with diamines and then with a monovalent alcohol. They are useful as stabilizers of organic materials subject to oxidative and thermal degradation.