The distribution of pores and the mechanical properties of materials are the key factors in preparing satisfactory low-k films. In the present study, a kind of silsesquioxane-polyethylene glycol (SSQ-PEG) was synthesized and used as a template to make the distribution of pores more even in the low-k films. The crosslinking density of films could be adjusted by the sol-gel of tetramethoxysilane/dimethoxydimethylsilane with various pro-portions. The porosity of films could also be adjusted with different proportions of pendant PEG chains introduced. A dielectric constant as low as 2.1 had been achieved for nanoporous polyorganosilicate films with good tenacity. (c) 2006 Wiley Periodicals, Inc.