In recent work we have reported the synthesis and physical properties of near-linear Ln(II) (Ln = lanthanide) complexes utilizing the bulky bis(silylamide) {N(SiiPr(3))(2)}. Herein, we synthesize trigonal-planar Ln(II) complexes by employing a smaller bis(silylamide), {N(SitBuMe(2))(2)} (N**), to study the effects of this relatively rare Ln geometry/oxidation state combination on the magnetic and optical properties of complexes. We show that the charge-separated trigonal-planar Ln(II) complexes [K(2.2.2-cryptand)][Ln(N**)(3)] (Ln = Sm (1), Eu (2), Tm (3), Yb (4)) can be prepared by the reaction of 1.5 equiv of [{K(N**)}(2)] with LnI(2)THF(2) (Ln = Sm, Yb) or LnI(2) (Ln = Eu, Tm) and 1 equiv of 2.2.2-cryptand in Et2O. Complex 3 is the first structurally characterized trigonal-planar Tm(II) complex. In the absence of 2.2.2-cryptand, [K(DME)(3)][Sm(N**)(3)] (5) and [Ln(N**)(2)(mu-N**)K(toluene)(2)] (Ln = Sm (6), Eu (7)) were isolated in the presence of DME (dimethoxyethane) or toluene, respectively. The 1:1 reaction of [{K(N**)}(2)] with LnI(2)THF(2) (Ln = Sm, Yb) in THF gave the four-coordinate pseudo-tetrahedral Lewis base adducts [Ln(N**)(2)(THF)(2)] (Ln = Sm (8), Yb (9)) and the cyclometalated complex [Yb(N**){N(SitBuMe(2))(SitBuMeCH(2))}(THF)] (10). Complexes 1-10 have been characterized as appropriate by single-crystal XRD, magnetic measurements, multinuclear NMR, EPR, and electronic spectroscopy, together with CASSCF-SO and DFT calculations. The physical properties of 1-4 are compared and contrasted with those of closely related near-linear Ln(II) bis(silylamide) complexes.