Most of transition metal(II) carboxylates were reported to exist as multinuclear complexes due to the multibinding modes of the ligands 1,2. For example, most of the copper(II) carboxylates were dinuclear with the paddle-wheel structure 3-7 , while other metal(II) complexes (Mn, Co, Ni and Zn) were found to form polymeric structures 8-11. Hence, these complexes are attracting the interests of many researchers in various fields, such as catalysis, molecular electronics and molecular magnetism. The main reason is because they are easily prepared from relatively low cost, nontoxic and readily accessible starting materials and readily characterized by conventional analytical methods. However, these complexes are yet to be commercially used as functional materials due to physical limitations, such as insolubility, high-melting and low-decomposition temperatures. Currently, our research group is focused on designing, synthesizing and characterizing thermally stable and low melting temperatures magnetic metal(II) carboxylates to function as molecular magnetic, photonic and electronic materials and as precursors for functional coordination polymers. This paper reports the synthesis, structural, magnetic, thermal, optical and redox properties of three complexes of 2-hexyldecanoato ligand (L) with Cu(II) (1), Ni(II) (2) and Co(II) (3). These complexes were obtained as room-temperature viscous liquids from the reaction of NaL with the

Copper(ii) complexes exhibiting temperature-dependent mesomorphisms.