Fully cyclized, soluble phenylethynyl-terminated ether imide oligomers of 2.0-10.0 kg/mole (Mn) were prepared in high yield by the reaction of 2,2'-Bis[4-(3,4-dicarboxyphenoxy)phenyl]-propane dianhydride (Bisphenol- A Dianhydride, BPADA) with a stoichiometric excess of p-/m- phenylene diamine and phenylethynylphthalic anhydride (4-PEPA) endcapper. The lower (Mp) oligomers displayed attractive low melt viscosity properties, and were successfully processed via thermal curing at 350-380°C for 30-90 minutes. The 3.0 kg/mole oligomers had a cured glass transition temperature (Tg) of 267°C and produced tough, solvent-resistant films. Excellent adhesion values to surface treated titanium alloys were produced by single lap shear measurements. Resin infusion molding has been conducted that permitted low void graphite fabric composite panels to be prepared. The diamine monomer bis(m-aminophenyl) methyl phosphine oxide (DAMPO) was synthesized via nitration and the reduction of diphenyl methyl phosphine oxide. Rigorous purification of this monomer enabled it to be used for the synthesis of high molecular weight polyetherimides. Both thermoplastic materials and thermosetting systems endcapped with either phthalic or phenylethynylphthalic anhydride, respectively, have been produced. Major emphasis has been placed on polyimides derived from 2,2’- bis(4-(3,4-dicarboxyphenoxy) phenyl) propane dianhydride (BPADA). High molecular weight homo- and copolyimides based on BPADA/DAMPO exhibited glass transition temperature values in the range of 215-223°C, and were completely amorphous. They displayed higher modulus and tensile strength values than the polyetherimide control based on meta-phenylene diamine, and also generated high TGA char yields in air. Phenylethynyl crosslinkable materials were effectively cured at 380°C to produce solvent resistant networks that were ductile, and which also generated high char yields, suggesting their possible utilization in fire resistant matrix systems. / Ph. D.