The layer-by-layer (LbL) assembled thin films containing tetraamino-thiacalix[4]arenes (1) and tetraamino-calix[4]arenes (2) were used as nanoreactor to synthesize in situ Ag nanoparticles (Ag NPs). UV-vis spectra and AFM images demonstrate that Ag NPs are included in the (1/Ag NPs)(n) and (2/Ag NPs)(n) multilayer films. The silver ions are absorbed through cation-pi interaction and calix[4]arene-metal ion coordination interaction and are reduced into Ag NPs by calix[4]arenes. TEM images indicated that Ag NPs within aminocalix[4]arene multilayers were highly dispersed and uniform. Moreover, the mean size of Ag NPs is smaller than 10 nm. (C) 2009 Elsevier Inc. All rights reserved.