Radiation detection material is a central component of nuclear technology fmding applications in many critical fields.Developing a highly radiation-sensitive material that shows a facilely detectable response to ultra-low dosage of radiation is a longterm research target and remains to be a challenge.Previously reported most optimal chemical radiation dosimeter can detect low-dosage X-and γ-ray radiations down to 10-4 Gy.We document here a new photoresponsive coordination polymer showing upgraded radiation detection capabilities with the detection limit on the radiation dose one order of magnitude lower than the previous record.The radiation induced photoluminescence quenching process was elucidated by multiple spectroscopic characterizations.