The influence of the reactive endgroup on the synthesis, cure behavior and network properties of thermosetting polyetherimides was investigated. Reactive phenylethynyl, ethynyl and maleimide terminated etherimide oligomers were prepared and characterized. Optimal reaction conditions were established to produce fully endcapped oligomers with imidized structures and controlled molecular weight. The phenylethynyl and ethynyl endcapped systems were synthesized by ester-acid methods. The maleimide endcapped system utilized an amic-acid route. Phenylethynyl endcapped oligomers had good processibility and were thermally cured at high temperatures (350-380 degrees C). The networks exhibited good thermal and hydrolytic stability and good adhesion strength, and are candidates for "primary" bonding adhesives. In contrast, more reactive ethynyl and maleimide endcapped systems were prepared as "secondary" bonding materials, which could be cured at temperatures lower than that of the T-g of the primary structure. Lap shear test results obtained from NMP-cast/methanol-extracted scrim-cloth-supported precursors confirmed that good adhesion to titanium at both room temperature and at 177 degrees C was achieved when cured at 250 degrees C - 280 degrees C. High glass transition temperatures and good thermal stability were achieved as determined by thermal analysis (DSC, TGA and DMA). Solvent extraction measurements confirmed that very high gel fractions were obtained, which is consistent with good chemical resistance. The influence of molecular weight between crosslinks (Mc) on thermal and mechanical behavior was also investigated for 2,3, 5, 7 and 10k initial (M) over bar(n) values. Lower molecular weight oligomers exhibited lower T-g and cure temperatures, but higher cured network crosslink densities afforded higher T-g and higher gel fractions, but with reduced toughness.