Novel flat crown ether molecules have been characterized in silico using density functional theory. Monomer units of Si2C3 with a planar tetracoordinate carbon (ptC) atom have been used as building blocks. Alkali (Li+, Na+, K+, Rb+, and Cs+) and alkaline-earth (Be2+, Mg2+, Ca2+, Sr2+, and Ba2+) metal ions, and uranyl (UO (Formula presented.)) ion selective complexes have also been theoretically identified. The high symmetry and higher structural rigidity of the host molecules may likely impart higher selectivity in chelation. The potential energy surface of the parent elemental composition, Si2C3H2, has been investigated using coupled-cluster (CC) approximation. The molecule with a ptC atom within the latter is a low-lying isomer lying 12.41 kcal mol−1 above the global minimum at the CCSD(T)/cc-pVTZ level. The crown ether molecules identified here could theoretically be considered the derivatives of the ptC atom isomer. Theoretical binding energies (ΔE; 0 K) and thermally corrected Gibbs free energies (ΔG; 298.15 K) for crown ether molecules have been computed to gauge their binding affinities. © 2020 Wiley Periodicals LLC