Disclosed are labeled cMet binding peptides suitable for optical imaging in vivo. The imaging agent comprises a conjugate of formula I, wherein the substituents are defined in the specification. The peptides are labeled with an optical reporter group suitable for imaging in the red to near-infrared region. Also disclosed are pharmaceutical compositions and kits, as well as in vivo imaging methods, especially of use in the detection, staging, diagnosis, monitoring of disease progression or monitoring of treatment of colorectal cancer (CRC).
