Abstract: Novel pyrazole-containing compounds useful as light-stabilizers for polymers, their Ni, Zn, Cu, and Co metal complexes, and methods for the synthesis of such complexes are provided. The compounds include a hindered amine light stabilizer (HALS) such as a substituted piperidine, thereby incorporate the properties of UV absorbers and redical scavengers. The compounds are of the formulas I and II, ##STR1## where R.sub.1 is phenyl, R.sub.2 is methyl, X is oxygen or sulphur, Z is oxygen or N-aryl, and R.sub.3 is hydrogen, alkyl, a derivative of carboxyacryloyl or carboxybenzoyl or a derivative of pyrazole. The compounds and their metal complexes are highly compatible with various polymers, thermostable, and retain their photostability under conditions of continuous and intensive irradiation. Methods for the synthesis of metal complexes include the reaction of: (a) a compound with metal acetate; or (b) a metal complex with anhydride or a pyrazole derivative.