The interaction of the thionucleobase 2-thiouracil with the triethylphosphinegold(I) cation has been examined employing ab initio molecular orbital theory. Deprotonation of 2-thiouracil (2-TUH) and subsequent association with [Et3PAu](+) leads to the formation of [Et3PAu(2-TU_H)]; a comparison of calculated and experimental geometric parameters reveals a high degree of agreement. The interaction of two [Et3PAu](+) cations with twice deprotonated 2-TUH indicates that the most stable dinuclear structure is one where coordination occurs via the sulfur and one of the nitrogen atoms leading to almost linear P-Au-S and P-Au-N arrangements, respectively.