A photodegradable supramolecular polymer was constructed using cucurbit[8]uril (CB[8]) and an alkoxyanthracene guest. The monomeric unit was photostable because of the intramolecular donor-acceptor interaction. However, upon complexation with CB[8], the photolysis of alkoxyanthracene was enhanced, which endowed the supramolecular polymer with great photoreactivity.