We describe the synthesis and energy-transfer characteristics of a [2.2]paracyclophane-based through-space-conjugated dimer consisting of two stacked pi-electron systems. Photoexcited energy transfer by the Forster mechanism from the donor to acceptor pi-electron systems occurred efficiently (energy-transter efficiency: Phi(ET) > 0.999) with a rate constant (k(ET)) of 10(12) s(-1).