The curing of liquid crystalline (LC) epoxides containing phenyl benzoate mesogens was studied under applied ac electric fields. When curing reactions began under a low-frequency electric field (similar to 1 V/mu m), parallel molecular orientation slowly changed to perpendicular to the field, because a crossover (cutoff) frequency of molecular orientation shifted to much lower frequencies as the curing reaction took place. As a result, the cured networks possessed orientation perpendicular to the applied ac electric fields regardless of the initial frequency. Due to electrohydrodynamic effects, curing reactions under a low-frequency electric field proceeded faster than those at high frequency. Electric fields also affected formation of the LC structure, in particular, in smectic networks. Curing of LC epoxides with twin mesogen architecture under an ac electric field produced a smectic-A like structure with a fan shape-like texture, whereas curing without an external field formed a disclination rich texture, The oriented smectic network possessed high orientation as well as high translational order. The mechanical properties of the oriented smectic-like network showed a negative CTE as well as linear load-extension behavior in the rubbery regime. These characteristics can be explained in terms of the smectic layer spacing and the lateral spacing between mesogenic groups as confirmed by X-ray diffraction measurements.