The title complex, [Na(C18H22O5)(H2O)]2[Co(NCS)4], consists of two aqua(2,3-naphtho-15-crown-5)sodium complex cations and one [Co(NCS)4]2 complex anion, which has crystallographic overline 1 symmetry. In the anion, the CoII centre is coordinated by the N atoms of four NCS ligands in a distorted tetrahedral geometry. In the complex cations, the NaI centre is coordinated by five O atoms of the 2,3-naphtho-15-crown-5 ligand and one water O atom. The complex molecules form a two-dimensional network via weak O—H...S interactions between adjacent cations and anions
