A series of phenylethynyl-terminated imide oligomers were prepared by the reaction of aromatic dianhydride(s) with a stoichiometric excess of aromatic diamine(s) at calculated number average molecular weights of 1500-9000 g mol-1 and end-capped with phenylethynylphthalic anhydrides in N-methyl-2-pyrrolidinone. Unoriented thin films cured in flowing air to 350-degrees-C exhibited tensile strengths and moduli of 105.5-139.3 MPa and 2.8-3.2 GPa at 23-degrees-C, respectively, with good retention of properties at 177-degrees-C. Stressed film specimens exhibited excellent resistance to a variety of solvents after a 2 week exposure period at ambient temperature. One phenylethynyl-terminated imide oligomer was selected for more extensive evaluation and gave high fracture toughness, adhesive and composite properties. The chemistry, physical and mechanical properties of these materials are discussed.