The polymer-to-ceramic transformation generally results in the release of gaseous products that leave behind a variety of pores. These porous materials can be applied as good adsorbents for various organic water contaminants. However, they cannot be employed to decompose organic adsorbates due to their low solid acidity. Oxide catalysts like TiO2, ZnO, WO3, F2O3, etc. are known to possess high solid acidity for photodegradation of organic compounds. In this work, ZnO was incorporated into polydimethyl siloxane followed by pyrolysis at 700°C to obtain porous SiOC/ZnO nanocomposites and their adsorption and photocatalytic activities were studied. The specific surface area of SiOC/ZnO porous ceramics (pore-size ~4 nm) was lower than that of pure SiOC ceramics (pore-size <2 nm). Pure SiOC porous ceramics showed no significant adsorption and photocatalytic activity for methylene blue due to its high microporosity and low solid acidity, respectively, whereas mesoporous SiOC/ZnO nanocomposite demonstrated higher adsorption and photocatalytic activity.