Solvothermal reactions of CuI with isopropanol, 4,4′-bipyridine, I₂ and a small amount of water in MeCN produced one coordination compound [isopropylviologen][CuI₃] (isopropylviologen = N,N′-diisopropyl-4,4′-bipyridinium) (1). The dielectric constants of the single crystal of 1 along the three crystal axes are different with the largest diversity ratio of 3.3, showing dielctric anisotropic behavior. Under low temperature (<273 K) or medium electric field frequency range (1 KHz–1 MHz), the dielectric constant of the title compound is nearly unchanged, exhibiting a temperature/frequency-independent characteristics. The crystalline powder of 1 has a low dielectric constant and low dielectric loss in the medium electric field frequency range, which is comparable to the traditional low-k material SiO₂.