The reactions of CoX2 (X=Br, Cl) with the planar, bidentate bridging ligand 2,1,3-benzothiadiazole (btd) in Me2CO led to the 2D coordination polymers {[CoBr2(btd)]}n (1) and {[CoCl2(btd)]}n (2). The structure of 1 was determined by single-crystal X-ray crystallography. Complex 1 (C6H4Br2CoN2S, monoclinic, P21/m, a=3.742(3), b=13.075(9), c=9.092(6) Å, β=90.09(2)°, Z=2, θ–2θ, R1=0.0298, wR2=0.0793) consists of {[Co(μ-Br)2]}n linear chains running along the a axis linked via μ-btd ligands along the b axis. The columns of stacked btd molecules present in the crystal structure of the free ligand are maintained in the lattice of 1. XRD data revealed that 2 is isostructural with 1. The magnetic properties of both complexes can be explained by the presence of a very weak ferromagnetic intrachain Co···Co exchange interaction through the (μ-X)2 bridges and a moderate antiferromagnetic Co···Co interaction through the μ-btd bridges. The new complexes were also characterized by EPR, IR, and UV/VIS spectra, and all data are discussed in terms of the nature of bonding and known structures.