In the present investigation estimation of the size of nano-aggregation has been carried out in the binary mixture of cholesteric and nematic compounds, namely, cholesteryl nonanoate (CN) and p-methoxybenzylidenep- ethylaniline (MBEA), which exhibits a very interesting liquid crystalline twisted grain boundary (TGB) phase and reentrant smectic-A phase. The chiral liquid crystalline TGB phases and reentrant smectic-A phases have been observed at different concentrations and at different temperatures. The existence of TGB and reentrant smectic-Aphases is confirmed byDSC and optical microscopic studies. The variation of optical anisotropy has been discussed. Present study clearly illustrates that, the nano aggregated size of the given molecules decreases with increasing the temperature. In SmB phase, small nano aggregated size of themolecules (35 nm- 40 nm) are observed. But in SmE phase, nano aggregated size of the molecules are bit large enough to show the value of 49 nm.