The goal of this study is to characterize the polyphenolics of the extracts from the skin of Punica granatum. L (pomegranate) and Quercus suber (cork oak). The measurements were performed quantitatively and complexing reactions with metals were characterized for use as sensors in aqueous solution. The qualitative analysis of these extracts by thin-layer chromatography reveals the presence of polyphenols in the extracts that was confirmed by the determination of total polyphenols. These analyses are complemented by high-performance liquid chromatography that shows that Punica granatum. L and Quercus suber are rich in bioactive compounds which affects their reactions with metals. Devices based on the components of the plants reveals high sensitivity and a linear relationship with cadmium ions. The lowest measured concentrations of cadmium were 10−10 M for the pomegranade extract and 10−9 M for the acorn extract.