Titled materials and their preparation. The materials contain a moiety such as, for example, 4-oxy-3,5-dimethyl-2,6-dibromobenzyl which can impart a high degree of thermal and hydrolytic stability to the materials, for example, epoxy thermosets such as in electronic encapsulations. For example, when used in electronic encapsulation formulations, these materials can provide a substantial increase in electronic device reliability. Their preparation involves an alkylation of an aromatic ring, for example, such as a Friedel-Crafts alkylation with 4-bromomethyl-3,5-dibromo-2,6-dimethylphenol or with 4-hydroxymethyl-3,5-dibromo-2,6-dimethylphenol.