Abstract: Using 2-amino-4-bromophenol, 4-cyanobenzaldehyde, p-bromobenzaldehyde and (trimethylsilyl) acetylene as raw materials, two new thermosetting benzoxazole resins, benzoxazole arylalkyne nitrile resin (PBON) and benzoxazole arylalkyne resin (PBOA), were successfully synthesized by coupling method. The thermal curing process of PBON and PBOA was studied by differential scanning calorimetry (DSC). The heat resistance of the cured PBON and PBOA was analyzed by thermogravimetric analysis (TGA). The dielectric properties of the cured PBON and PBOA were studied by broadband dielectric method. The solubility of PBON and PBOA was also studied. Results show that two monomers have good solubility in ordinary solvents, such as tetrahydrofuran (THF) and dimethyl sulfoxide. The viscosity of THF solution of PBON and PBOA is 870 mPa·s and 430 mPa·s, respectively. The viscosity of THF solution of both resins is low, which is suitable for processing by solvent method. Both of the cured PBON and PBOA have excellent thermal stability. The decomposition temperature of 5% mass loss (T_d5) of the cured PBON is 596 ℃, and the carbon yield ratio at 900 ℃ (Y_{c, 900}) is 69.7% in nitrogen. For the cured PBOA, T_d5 is 592 ℃ and Y_{c, 900} is 79.5% in nitrogen. Both of the cured resins have good mechanical properties, and can be used as structural parts. The flexural strength of the cured PBON at room temperature is 48.2 MPa, which is slightly lower than that of the cured PBOA, which is 59.5 MPa. However, the flexural modulus of the cured PBOA is almost equal to that of the cured PBON. The dielectric constant of the two cured resins at 1 MHz is lower than 2.5 and the dielectric dissipation factor of them is lower than 0.06.