Dendrimers 6G(i) (i=1-4) consisting of an anthracenecore and Frechet dendrons which are attached via a CH(2)OCH(2) chain in the 9-position undergo quantitative and completely reversible intramolecular [4pi+4pi] cycloaddition. The process can be monitored by absorption and fluorescence measurements. The Frechet dendrons act as an energy funnel that collects and focuses the photon energy but does not