Seven novel p-ethynylbenzoyl ester momoners (EBEs) have been synthesized in high yield and purity and characterized by GPC and X-ray, FTIR, Raman, and H-1 NMR spectroscopy. The monomers are crystalline. Five of the monomers polymerized without melting. Thermal polymerization in N2 produced highly cross-linked resins with polymerization exotherms centered between 204 and 250-degrees-C. The monomers are liquid crystalline or crystalline during polymerization and yield polymers retaining some order. They polymerize to high conversion in spite of their rigid matrix, which was attributed to the fact that their ethynyl groups interdigitate to a certain degree. Methylhydroquinone- and chlorohydroquinone-bis(4-ethynylbenzoate) melt to a nematic mesophase just before they polymerize. The monomers polymerized in the solid state (crystalline) exhibited little or no polymerization shrinkage (0-2.3%). 4,4’-Dihydroxybiphenyl-bis-(4-ethynylbenzoate) showed zero polymerization shrinkage. A new processing technique was used to polymerize the monomers which neither melt or have a softening point. EBEs were thermally polymerized under moderate pressure to yield high modulus, cohesive polymer plates. Polymer plates could be made from 2,6-dihydroxynaphthalene-, 1,5-dihydroxynaphthalene-, and 4,4’-dihydroxybiphenyl-bis(p-ethynylbenzoate) that were void free and had storage moduli, E’, from 4.5 to 4.8 GPa at room temperature. Using DMA and TMA it was found that all polymers except the 2,6-dihydroxynaphthalene-ester had T(g)’s from 345 to 440-degrees-C, 50 to 140 deg higher than their polymerization (processing) temperatures! EBE polymers have very high E’s and T(g)’s, much higher than those of normal amorphous cross-linked polymers, because they are highly cross-linked rodlike materials. Using TGA under N2, the polymers showed a 5% weight loss between 446 and 485-degrees-C, a maximum decomposition temperature from 554 to 598-degrees-C, and anaerobic char yield of 60 to 66% at 800-degrees-C. Isothermal aging for poly(hydroquinone-bis(p-ethynylbenozate)) showed that the polymer retained more than 70% of its initial weight after 100 h at 320-degrees-C in air. Of all the polymers, poly(4,4-dihydroxybiphenyl-bis(p-ethynylbenzoate)) showed the best combination of thermomechanical and thermal properties (4.5-GPa storage modulus at room temperature, T(g) over 415-degrees-C, and initial decomposition temperature over 470-degrees-C).