This book describes the preparation of nanostructured functional polymeric composites, from synthesis of nanofiller to obtained solid composite. Filler and composite are characterized with many spectroscopic, diffractometric and thermomechanical techniques. Their characterization want to study the possible interaction between filler and polymer host, to use better the features of inserted material. I chose three nanosize fillers: Cobalt HexaCianoFerrate, Yttrium Aluminum Garnet doped with Cerium and Carbon Nanotube. Hosting matrix is constituted by Poly- methylmethacrylate. CoHCF showed clear chromic features, The second filler, Ce: YAG has studied for its photoluminescence features. some peculiar optoelectronic and mechanic features. In particolar in the nanocomposites field for own opto-adsorbent properties. They succeed to combine exceptional chemical and mechanic strength, with adsorbent properties typical of microporous materials, and quasi-ideal opto-electronic properties. The poly-methylmethacrilate has chosen as matrix because of ductility, fast photo-polymerization, and high transparency.