A series of new ligands 5-(4′-alkylphenylazo)-3-phenylamino-2-thioxothiazolidin-
4-one (HL n) were synthesized from the coupling of 3-phenylamino-2-thioxothiazolidin-4-
one with aniline and its p-derivatives. These ligands and their Co (II) polymeric complexes of 
the [(Co) 2 (L n) 2 (HL n)(CH 3 COO) 2 (H 2 O) 2] n have been deduced from elemental 
analyses, IR, 1 H-NMR, X-ray diffraction and mass spectra as well as magnetic and therm