The synthesis, characterization and reactivity of linear and network macromolecules by chemical modification of amorphous poly(arylene ethers) with pendant amines were investigated. A new monomer, 3-aminophenyl-bis(4-fluoro phenyl)phosphine oxide was prepared by nitration and reduction of bis(4-fluoro phenyl)phenylphosphine oxide. Statistical incorporation of pendant aryl amines into linear polymers was achieved by copolymerization of the 3-aminophenyl-bis(4-fluorophenyl)phosphine oxide with another activated dihalide monomer such as 4,4'-dichlorodiphenylsulfone and bisphenol-A. Step polymerizations employing nucleophilic aromatic substitution with a dipolar aprotic solvent, toluene as the azeotroping agent, and a slight excess of potassium carbonate as the weak base was the preferred methodology. The concentration of amines along the polymer backbone was successfully controlled by varying the ratio of 3-aminophenyl-bis(4-fluorophenyl)phosphine oxide monomer relative to the other comonomers. Characterization of the pendant amines by proton NMR and potentiometric titration indicated good agreement between the charged amount and the incorporation of this monomer into the copolymer backbone. The pendant amines could be quantitatively converted to pendant phthalimides by reaction with phthalic anhydride. The pendant amines were also reacted to form crosslinkable groups such as maleimides and phenylethynyl phenyl imides. These were thermally treated to induce crosslinking and formed ductile networks which had improved solvent resistance and higher glass transition temperatures. The poly(arylene ethers) containing pendant amines were also reacted with an epoxy resin and 4,4'-diaminodiphenylsulfone to afford epoxy networks which had significant improvement in fracture toughness at selected compositions. Bis(o-aminophenol) monomers were investigated as precursors to poly(arylene ethers) having pendant amines by copolymerization with 4,4'-dichlorodiphenylsulfone and bisphenol-A. These studies resulted in insoluble gels, which suggested that reaction of both the o-aromatic amine and the phenolate with the activated dinalide was occurring. This was further confirmed by the successful oligomerization of o-aminophenol itself with 4,4'-dichloro diphenylsulfone, which afforded NMP soluble novel poly(sec-amino phenoxy diphenylsulfones) with high glass transition temperatures (Tg~276°C). / Ph. D.