A Jager type of ligand (L41) has been utilized for synthesizing 1D Fe(II) complex for multifunctional behavior. A redox-active tetrathiafulvalene (TTF) functionalized Schiff-base ligand is chosen as a chelating ligand to the Fe(II) center and ditopic linker 4,4'-bipyridine (bipy) is used to form a one-dimensional polymer, [Fe II (L41)(bipy)]n (64) (Fig. ). The magnetic profile shows a 8 K wide thermal hysteresis in the T vs T plot. The dielectric property measurement profile with respect to temperature exhibits a thermal hysteresis in the same region where the magnetic thermal hysteresis occurs (Fig. ). This synergistic change in the dielectric and magnetic properties come from the fact that there is a local structural change in the Fe(II) octahedron due to the spin-state change and also there is bending motion of the TTF moiety associated during SCO process (Fig. ). The ε' value is high in the LS state and low in the HS state . . The magnetic study reveals that the SCO occurred around 170 K without any hysteresis, and at low temperatures, the T value increases, which is due to ferromagnetic interaction between Fe III LS ions and the residual N≡C-Fe II HS-C≡N species (Fig. ).