The magnetic measurements as T vs T revealed that the complex 24 remained HS in the whole measured temperature range of 400 -50 K, which was expected for one Fe(II) center remain in a FeN3O3 surrounding with weak ligand field strength. In contrast, 24 exhibited LS to HS transition with T1/2↑ = 380 K and T1/2↓ = 323 K, exhibiting hysteresis width of 48 K in the very first cycle (Fig. ), where the T value reached 0.009 cm 3 mol -1 K and 3.11 cm 3 mol -1 K at room temperature and 400 K respectively. However, during the next heating and consecutive cooling cycles T1/2↑ value decreased to 371 K while T1/2↓ remained constant. Moreover, the HS to LS conversion in heating mode was more abrupt than the LS to HS conversion in cooling mode. The SCO phenomenon was further validated by DSC measurements, where a sharp endothermic and a broad exothermic transition at 375 K and 327 K were observed during the first heating and cooling cycle. A shift in the endothermic peak to 373 K was noticed during the second heating cycle, which is also accordant with the magnetic data. Additionally, sharp endothermic peak and the broad exothermic peak were consistent with the nature of abrupt spin transitions in heating and cooling cycles, respectively.