**4.** *In situ* **temperature measurements under microwave irradiation**

The *in situ* temperatures of the ethanol-hexane mixed solution and MBBA in the isotropic state under microwave irradiation were assessed with respect to the variation in 1 H chemical shifts with temperature for the sample solution located in the NMR probe. **Figure 2** shows the temperature dependence of the 1 H NMR signals of OH, CH2, and CH3 protons in ethanol (**Figure 2a**) and the CH2 and CH3 protons in hexane (**Figure 2b**) that were observed under temperature control with the NMR spectrometer. The 1 H chemical shift changes from that at 0°C (Δδ) were plotted as a function of the temperature.

Δδ plotted as a function of temperature was approximately linear within a small temperature range, as observed in methanol and glycol [40]. <sup>1</sup> H NMR spectra of individual protons were measured in the same sample at the same position in the probe and the temperature variation was measured under microwave irradiation. The *in situ* temperatures (CSC-temperature) of the individual protons in the sample solution under microwave irradiation were thus evaluated using the temperature variation of the <sup>1</sup> H chemical shifts. It is stressed that the *in situ* temperature of the bulk solution was accurately determined with the CSC*-*temperature for individual non-polar proton groups under microwave irradiation.
