The synthesis and characterization of a highly ordered macroporous US with regular arrays of spherical pores comparable to optical wavelengths are discussed. The sample has been successfully fabricated using colloidal crystal of poly (styrene-acrylic) (PSA) spheres as templates. The pore size is tunable in the range of 100-400 nm based on the size of PSA spheres. Transmission electron microscope (TEM) and scanning electron microscope (SEM) show that the exactly three-dimensional structure of the template has been imprinted in the final materials. XRD pattern indicates that the walls of the macroporous material are composed of 4 nm US nanoparticles making the absorption spectrum shift blue. The sample was also characterized by Raman spectroscopy and photo luminescent spectra (PL). (C) 2002 Elsevier Science Ltd. All rights reserved.