{Ba[Au(SCN)(2)](2)}(n): a three-dimensional net comprised of monomeric and trimeric gold(I) units.

The noteworthy structural feature of the title complex, poly[acetonitrile-tetra-µ(2)-thio-cyanato-barium(II)digold(I)], {[Au(2)Ba(SCN)(4)(CH(3)CN)]}(n), is that the bis-(thio-cyanato)-aurate(I) anion adopts both monomeric and trimeric motifs. The trimer unit has an Au⋯Au distance of 3.1687 (3) Å. In both the monomeric and trimeric units, the Au(I) atoms are also bonded to two S atoms. Within the trimeric unit, the Au(I) atoms exist in differing environments; one Au atom has a T-shaped three-coordinate geometry while the other has a square-planar four-coordinate geometry. The Au(I) atom of the monomer adopts a linear two-coordinate geometry. The extended structure can be described as a three-dimensional coordination polymer consisting of chains of Ba atoms bridged by thio-cyanate N atoms. These chains are cross-linked via the gold monomeric and trimeric units.