Thiocyanate is a hydrogen bond (H-bond) acceptor, but there are comparatively few studies of its hydrogen bonding propensity. To benchmark the hydrogen bonding between the A-site cations and the NCS -in these materials we therefore examined a hydrogen bond rich material, Gua(SCN). We redetermined the structure using a crystal present in commercially supplied GuaSCN. Gua(SCN) crystallises in space group P 1, with Z = 2. Its structure arises largely from the need to optimise its H-bonding, as it comprises H-bonded layers in the bc plane slip-stacked along the a direction [Fig. ]. These layers consist of a honeycomb lattice of NCS -ions, which lie approximately normal to the layer, and a bilayer of Gua + cations positioned at the centre of the honeycomb voids and which form a triangular lattice. Half of the NCS - ions point up and half down, and this up-down pattern is stripeordered along the b * direction. Each Gua + cation forms charge-assisted bifurcated hydrogen bonds to three NCS -ions: one to an N-terminus and two to an S-terminus. Likewise, the NCS -forms hydrogen bonds to three Gua + cations, one through its N-terminus and two through its Sterminus. These hydrogen bonds also cause the NCS -ions to tilt away from the a * direction along the c direction towards the Gua As each cage contains four distinct orientations of the Gua + cation, and is surrounded by twelve NCS -ligands, this means one quarter of all NCS -will be H-bond acceptors.