<p>Metal-doped endohedral borospherenes M@B₄₀ have attracted considerable attention since the discovery of the first boroshphenes B₄₀^−/0 in 2014. Systematical density functional theory investigations performed herein unveil the ground-state structures and coordination bonding patterns of a series of lanthanide-doped endohedral borospherenes Ln@B₄₀^0/+, including the doublet <i>C</i>_2<i>v</i> Ce@B₄₀⁺ (<b>1</b>, ²B₁), triplet <i>C</i>_2<i>v</i> Ce@B₄₀ (<b>2</b>, ³A₂), quartet <i>C</i>_2<i>v</i> Pr@B₄₀ (<b>3</b>, ⁴B₁), quintet <i>C</i>_2<i>v</i> Nd@B₄₀ (<b>4</b>, ⁵A₁), sextet <i>C</i>₂ Pm@B₄₀ (<b>5</b>, ⁶A), septet <i>C</i>_2<i>v</i> Sm@B₄₀ (<b>6</b>, ⁷A₂), octet <i>D</i>_2<i>d</i> Eu@B₄₀ (<b>7</b>, ⁸B₁), and octet <i>C</i>_2<i>v</i> Gd@B₄₀⁺ (<b>8</b>, ⁸A₂). Detailed principal interaction spin orbital (PISO) and adaptive natural density partitioning (AdNDP) bonding pattern analyses indicate that, with the number of unpaired α-electrons changing from n_α = 1, 2, 3, 4, 5, 6, 7, to 7 in the series, their coordination bonding energies decrease monotonically from <i>E</i>_c = 7.22, 6.93, 5.67, 4.85, 4.67, 4.29, 4.02, to 2.07&#xa0;eV, respectively, with the dominating percentage contributions of the Ln 5d-involved PISOs to the overall <i>E</i>_c increasing almost monotonically from 66 to 83%, while the minor contributions of the Ln 4f-involved PISOs varying between 0.3% and 12.1% and that of Ln 6s-involved PISO pairs remaining basically unchanged in a narrow range between 6% and 8%. In average, the dominating 5d-invloved PISOs in Ln@B₄₀ contribute about 72.8% to the overall <i>E</i>_c, 19.3% higher than that (53.4%) of the 6d-involved PISOs in the newly reported actinide-doped An@B₄₀^+/0/−, while the minor 4f-involved PISOs in Ln@B₄₀ contribute about 6.1% to <i>E</i>_c, 15.7% lower than that (21.8%) of the 5f-invloved PISOs in An@B₄₀^+/0/−, quantitatively unveiling the differences in coordination bonding patterns between Ln@B₄₀^+/0 and An@B₄₀^+/0/−.</p> Graphical Abstract <p></p>