High internal phase ratio emulsions (HIPREs) are stable microemulsions (oil-in-water or water-in-oil) prepared by mixing oil and water in the presence of appropriate surfactants in one or both phases to stabilize the interface. Those that contain surfactants in both oil and water are also called polyaphrons. This review enumerates the generation, properties of polyaphrons and their various applications in environmental remediation and materials synthesis. Specifically, the review addresses our current work in the applications of polyaphrons in liquid/liquid extraction for dilute solutions separations, in-situ treatment of non-aqueous solvent spills in the sub-surface, and the synthesis of extended porous materials using polyaphrons as templates in sol-gel science.