<p>In this work, a density functional theory (DFT) investigation is employed to design and explore a novel series of alkaline earthides by using azacryptand (complexant). Nine complexes are designed by intercalating alkaline earth metals (AEMs) inside and outside the complexant respectively <i>e.g.,</i> M⁺(azacryptand)M⁻ (where M⁺ and M⁻ are Be, Mg, Ca). All the DFT calculations are performed by using ωB97X-D functional along with 6-31G + (d,p) basis set. The studied complexes have high thermodynamic stability, as verified by their highly negative interaction energies (-23.54 to -49.13 kcal mol⁻¹). Moreover, earthides nature of complexes is validated through natural bond orbital (NBO), molecular electrostatic&#xa0;potential (MEP), frontier molecular orbital (FMO) and partial density of state (PDOS)&#xa0;spectra analysis, showing negative charge, excess electrons and position of HOMO (highest occupied molecular orbital) over outer AEMs. A remarkable first hyperpolarizability (β_o) upto 5.01 × 10⁴ au is recorded for studied complexes, highlighting the importance of larger acceptor metals in enhancing nonlinear responses. Moreover, two level model analysis is also carried to get comprehensive picture of controlling factor of hyperpolarizability. The absorption spectra are analyzed in the gas phase using the time dependent-DFT approach, indicates that all complexes except Be⁺(azacryptand)Mg⁻ are transparent in UV region. In addition, the application of an external electric field (+ 0.001 a.u.) led to a further decrease in band gaps and significant enhancement of hyperpolarizability <i>e.g.,</i> β_o increases from 5.01 × 10⁴ au o 6.72 × 10⁴ au for Ca⁺(azacryptand)Ca⁻. These results demonstrated that azacryptand-based alkaline earthides are promising candidates for NLO materials.</p>