The first coordination polymer of a bridging radical 1,2,3,5-dithiadiazolyl ligand is reported. Upon coordination with the La(hfac)3 fragment, the paramagnetic 4-(benzoxazol-2'-yl)-1,2,3,5-dithiadiazolyl (boaDTDA) ligand forms a one-dimensional (1D) alternating -[La(hfac)3-boaDTDA]n- polymer exhibiting ferromagnetic (FM) coupling between the radicals, mediated through the diamagnetic La(III) ion (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato).