Quasi-2D superconductivity behavior of Li_x(C₃H₁₀N₂)_0.32FeSe (x = 0.15, 0.25). (a) and (c) Temperature-dependent resistivity around T_c of Li_x(C₃H₁₀N₂)_0.32FeSe (x = 0.15, 0.25) under increasing magnetic fields. The lines are for examples (for μ 0 H = 9 T) of background contribution, as determined by a linear fit above 42 K, where fluctuation effects are expected to be negligible. (b) and (d) The fluctuation contribution to the conductivity Δ σ varies with temperature under external magnetic fields up to 9 T for Li_x(C₃H₁₀N₂)_0.32FeSe (x = 0.15, 0.25). The inset shows the fitting of Δ σ versus temperature with the quasi-2D Lawrence–Doniach model (green dash line) and 3D anisotropic Ginsburg–Landau model (brown solid line). (e) and (g) Expanded view of temperature dependence of magnetization for Li_x(C₃H₁₀N₂)_0.32FeSe (x = 0.15, 0.25) under external magnetic fields. The data are corrected for T-independent background. (f) and (h) 2D scaling of high-field magnetization curves for Li_x(C₃H₁₀N₂)_0.32FeSe (x = 0.15, 0.25), with inset showing 3D scaling behavior.