Polyimide oligomers (prepolymers) and resins of the PMR-15 type have been prepared from 5-norbornene-2,3-dicarboxylic half acid ester (NE), 3,3’,4,4’-benzophenonetetracarboxylic diester (BTDE) and a series of diamines including, and related to, 3,3’-diaminobenzophenone, viz. 3,3’-diaminobenzhydrol, 3-[(m,m’-diamino)benzhydryloxy]propyne (MDA-OMA) and 3,3’-diaminodiphenyl-alpha,alpha’-difluoromethane (FMDA). The PMR synthetic pathway (monomers-->prepolymer-->resin) has been assessed by dynamic mechanical thermal analysis. The T(g) values for resins incorporating BTDE are significantly lowered compared to that for PMR-15 itself. The fluorine-containing PMR-15 type of resin (from FMDA) is of higher thermal stability than PMR-15 itself.