New polymer organogelators, which are composed of poly(ethylene glycol), poly(propylene glycol), and poly(dimethylsiloxane)s as a polymer segment and L-iso-leucine and L-valine derivatives as a gelation-causing segment, were synthesized, and their organogelation properties were examined in organic solvents and oils. These polymer organogelators formed organogels in many organic solvents and oils, and their gels were thermally stable and had a high mechanical strength. Furthermore, the effects of the polymer backbone on the organogelation is discussed using FTIR spectroscopy, field emission scanning electron microscope observation, and analysis of thermal stability and strength of the organogel. (C) 2007 Wiley Periodicals, Inc.