Pentanol and Octanol are strong candidates to improve the blending stability of hydrous ethanol and diesel. Most of the available studies are limited to the stability assessment and properties characterization without combustion evaluation. In this study, the impact of ternary blends of pentanol/hydrous ethanol/diesel (Pe10E10D80) and octanol/hydrous ethanol/diesel (Oc10E10D80) on CI engine combustion and performance are investigated. The fuel characteristics are measured, and a thermogravimetric analysis is performed. A set of experiments are performed on a CI engine at a wide range of operating conditions. The experiments report that the peak cylinder pressures for Pe10E10D80 and Oc10E10D80 are lower than that of D100. The rate of heat release (RoHR) at premixed combustion phase is diminished but enhanced for diffusion combustion zone. Ignition delay and combustion duration increased for ternary blends. The BSEC and bsfc for Oc10E10D80 is lower than D100, but both for Pe10E10D80 are higher than D100. The BTE of Oc10E10D80 is higher than D100, but Pe10E10D80 has lower BTE. The smoke, NOx, CO and CO2 emissions are reduced by 73%, 33%, 83%, and 56%, respectively. Pentanol and octanol addition to hydrous ethanol/diesel blend achieves better blending stability with improved engine performance and reduced emissions.