The new linear molecule Ag-C≡C-Cl has been detected and fully characterized by means of rotational spectroscopy. It was synthesized by laser ablation of a silver rod in the presence of a gaseous sample containing a low concentration of CCl4 in argon, cooled to a rotational temperature approaching ∼1-3 K through supersonic expansion, and analyzed by chirped-pulse, Fourier transform microwave spectroscopy. Six isotopologues were investigated, and for each the spectroscopic constants B0, D(J) and χ(aa)(Cl) were determined. The B0 values were interpreted to give the following bond lengths: r(Ag-C) = 2.015(14) Å and r(C-Cl) = 1.635(6) Å, with r(C≡C) = 1.2219 Å assumed from an ab initio calculation at the CCSD(T)/aug-cc-pV5Z level of theory. The Cu analogue Cu-C≡C-Cl was similarly identified and characterized.