(Figure ). The field dependence of magnetization studies was performed from 0 -5 T at 2 K (Figures S25). The d(T)/dT vs. T plot for complex 1 in cooling mode (Figure , blue curve) exhibits two broad maxima centered at around 223 and 135 K (Figure ). These maxima represent the T1/2 temperature for spin-state switching between HS state to HS:LS intermediate phase and finally to LS state, respectively. In heating mode from 2 -350 K, the T vs. T curve is identical to the cooling curve, indicating a reversible spin-state switching feature in 1 at the measured sweep rate. Overall, magnetic studies confirm a reversible two-step spin-state switching in 1.