Cs2Cd(C2H)(2)(C-2) was synthesized by heating known Cs2Cd(C2H)(4) either in a dry argon atmosphere at 200 degrees C or under ammonothermal conditions (130 degrees C, similar to 100 bar). The crystal structure of the resulting dark orange-brown microcrystalline material was solved and refined from synchrotron powder diffraction data (Cmcm, Z = 4). Cs2Cd(C2H)(2)(C-2) is composed of Cd2+ cations tetrahedrally coordinated end-on by four acetylide groups. Two of them are terminating C2H- groups, whereas the other two positions are occupied by bridging C-2(2-) anions. Thus, a polymeric (1)(infinity)[Cd(C2H)(2)(C-2)(2/2)(2-)] chain-like anion results and these chains are separated by Cs+ cations. So obviously Cs2Cd(C2H)(2)(C-2) is formed from Cs2Cd(C2H)(4) by a condensation reaction of two of its four C2H- groups under the release of one acetylene (C2H2) molecule. This reaction mechanism is supported by DSC/TGA measurements, and the crystal structure of Cs2Cd(C2H)(2)(C-2) is further supported by IR spectroscopic investigations.