Fluoroalkyl end‐capped cooligomers containing diphenylacetylene segments [RF‐(DPMA)x‐(Co‐M)y‐RF] were prepared by reaction of fluoroalkanoyl peroxide with 4‐(phenylethynyl)phenyl methacrylate (DPMA) and radical polymerizable comonomers such as N,N‐dimethylacrylamide (DMAA) and acryloylmorpholine (ACMO) under very mild conditions. Fluorinated cooligomers containing diphenylacetylene segments thus obtained exhibited a good solubility in a variety of organic solvents. These fluorinated cooligomers were also applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate) (PMMA) to exhibit not only a good surface active property imparted by fluorine but also a fluorescent characteristic related to diphenylacetylene segments on their surface. In addition, these fluorinated cooligomers could form the nanometer size‐controlled fluorinated molecular aggregates in chloroform. Interestingly, some benzenes and biphenyl (BP) derivatives could interact with these fluorinated oligomeric aggregates as guest molecules, and in particular 2‐chloro‐5‐nitrobenzotrifluoride (CNB) was most effective for enhancing the fluorescent intensity of these guest molecules. Copyright © 2009 John Wiley & Sons, Ltd.