A multi-functional epoxy resin with good high temperature properties allowing prolonged service at temperatures above 120.degree. C. is derived from a precursor of formula (I): ##STR1## in which R.sup.3 to R.sup.8 inclusive are independently selected from hydrogen, C.sub.1 to C.sub.3 alkyl or halo-alkyl and R.sup.9 is hydrogen, alkyl or halogen, and in which n has the value 0, 1 or 2. The precursor (I) may be self-coupled or cross-coupled with precursors of other epoxy compounds of the TGDDM type. Such cross-coupling gives rise to a complex mixture containing not only the mixed product, but also the self-coupled products of each constituent. Regardless of the precise chemical make-up of the mixture, the observed glass transition temperature is higher than for TGDDM resins formed without precursor (I). If the substituent at the R.sup.9 position is alkyl or halogen, oligomer formation is suppressed and a less complex mixture results.