A metal-organic framework (MOF)-based highly selective and sensitive probe (UiO-66@Butyne) for the detection of Hg(II) ion has been developed. To the best our knowledge, this is the foremost example of a chemodosimeter-based approach to sense Hg(II) ion using a MOF-based probe. The chemical stability of UiO-66@ Butyne renders the sensitive detection of Hg2+ ion in an aqueous phase. UiO-66@Butyne has been found to be selective for Hg(II) ions even in the presence of other metal ions.