In the present work, fluorescence anisotropy studies of BODIPY (pyrromethene 546 or CHBFN) dye have been performed and found that it has a potential to be used as a thermal probe to measure the temperature of microfluid. It is well-known that a dye rotates in its excited state, so to control the molecular rotation of the dye in the excited state, sorbitol is used in the solution. It has been found that adding sorbitol, fluorescence anisotropy increases, fluorescence lifetime decreases. It has been found that adding sorbitol, temperature sensitivity increases. To study the effect of -CH groups on fluorescence properties, another BODIPY (pyrromethene 597 or CHBFN) dye is also used, as CHBFN and CHBFN have similar structures with a difference of only -8CH groups. It has been found that CHBFN has superior properties over CHBFN, i.e., pyrromethene 597 shows larger temperature sensitivity as compared to pyrromethene 546, even without the addition of sorbitol.