Provided is a family of intramolecularly quenched imaging agents for use in both in vivo and in vitro imaging that contain at least one enzymatically cleavable oligopeptide and two fluorophores or a fluorophore and a quencher. When subjected to proteolytic cleavage, at least one fluorophore is unquenched and becomes capable of producing a fluorescent signal upon excitation with light of an appropriate wavelength. Also provided are in vivo and in vitro imaging methods using such imaging agents.
