Dispersion of filler(s) in polymeric compositions are improved by the use of a polymer-filler coupling compound, Q—A—B, wherein Q comprises a dipolar nitrogen-containing moiety that can form a 1,3 dipolar addition to an unsaturated carbon-carbon bond; B is an oxazoline, thiazoline, alkoxysilane or allyltin moiety, and A is a linking atom or group that forms a bridge between Q and B.