Porous organic polymeric films having multiple discrete cavities can be prepared by applying a water-in-oil emulsion that includes a cavity stabilizing hydrocolloid on the inner walls of the multiple discrete cavities to a substrate. The multiple discrete cavities can also include organic catalytic materials for various catalytic reactions, markers materials for security applications, or the multiple discrete cavities can be used to increase opacity, hydrophobicity, or other desirable properties compared to nonporous organic polymeric films composed of the composition and dry thickness. Water and oil from the applied water-in-oil emulsion can be removed by evaporation in a suitable process, and the applied porous organic polymeric film can be provided as a uniform material or in a patternwise fashion.