In the crystal structure of the title 1:2 adduct, [Zn(2)(NCS)(4)(C(4)H(8)N(4))(2)]·2[Zn(NCS)(2)(C(4)H(8)N(4))(2)] or (Ia)·2(Ib), each Zn(II) atom is coordinated in a distorted tetra-hedral geometry by four N atoms from two triazole rings of two 4-amino-3,5-dimethyl-1,2,4-triazole (admt) ligands and two NCS(-) ligands. In (Ia), double N(1):N(2)-bridging admt ligands connect two Zn(II) atoms, forming a dimer with a Zn(2)(admt)(2) six-membered metallacycle located on a crystallographic inversion center. In (Ib), the admt ligands exhibit monodentate N(1)-coordination modes. Weak N-H⋯N, N-H⋯S and C-H⋯S hydrogen bonds play an important role in the inter-molecular packing. The S and C atoms of two thiocyanato ligands are disordered over two sets of sites in ratios of 0.57 (3):0.43 (3) and 0.63 (3):0.37 (3), respectively.