Smart material nanoassemblies that can simultaneously sense and shoot low-level contaminants from air and water are important for overcoming the threat of hazardous chemicals. Graphene oxide (GO) sheets deposited on mesoscopic TiO2 films that underpin the deposition of Ag nanoparticles with UV irradiation provide the foundation for the design of a smart material. The Ag particle size is readily controlled through precursor concentration and UV irradiation time. These semiconductor–graphene oxide–metal (SGM) films are SERS-active and hence capable of sensing aromatic contaminants such as 4-nitrobenzenethiol (4-NBT) in nanomolar range. Increased local concentration of organic molecules achieved through interaction with 2-D carbon support (GO) facilitates low-level detection of contaminants. Upon UV irradiation of 4-NBT-loaded SGM film, one can induce photocatalytic transformations. Thus, each component of the SGM film plays a pivotal role in aiding the detection and degradation of a contaminant dispersed in aqueous solutions. The advantage of using SGM films as multipurpose “detect and destroy” systems for nitroaromatic molecules is discussed.