Electrides are excess electron compounds with excellent nonlinear optical properties. Herein we report the geometric, electronic, and nonlinear optical properties of C6Li6−M3O electrides. These electrides are designed by doping superalkali (Li3O, Na3O, and K3O) on hexalithiobenzene (C6Li6). Density functional theory results reveal that charge transfer occurs from M3O to hexalithiobenzene (C6Li6). Ab-initio molecular dynamics (AIMD) simulation at room temperature reveal that these complexes are quite stable thermodynamically. These electrides possess lower HOMO−LUMO energy gaps and crucial excitation energies than pristine C6Li6. NLO response of the designed electrides is studied through first hyperpolarizability (βtot), second hyperpolarizability (γtot), and the frequency-dependent second harmonic generation (SHG), electro-optic Pockel’s effect (EOPE), electric field-induced second harmonic generation (ESHG), Electro-optic Kerr effect (EOKO), Hyper-Rayleigh Scattering coefficient (βHRS) and nonlinear refractive index (n2). Remarkably high frequency induced dc-Kerr effect (upto 3.0×1016 au) and ESHG (upto 2.2×1015 au) are computed for the designed electrides. Moreover, these electrides also exhibits enormously high quadratic nonlinear refractive index (upto 2.6×10−6 au). This work provides new insights for designing stable organometallic electrides (C6Li6−M3O) with enhanced NLO response.