Sintering behavior in LiNaNbO (LNN-12) ceramics has been investigated by analyzing the microstructures of the samples sintered at different temperatures (1050-1250 °C) and durations (1-6 h) to optimize the sintering conditions. An excess amount of LiCO was added (1, 3, 5 mol%) to stoichiometric LNN-12 in order to compensate for the probable alkaline element loss at higher optimized sintering temperature. The addition of excess LiCO into the starting materials and the effect of it on microstructure and electrical properties were investigated. Microstructural study of LiCO-added samples revealed abnormal grain growth, a characteristic feature of liquid phase sintering due to the low melting LiCO. The temperature and frequency dependence of dielectric constant shows two phase transitions in temperature dependence and low-frequency dispersion in the frequency dependence of dielectric plot. The observed frequency dispersion is attributed to dominant DC conductivity. The conduction mechanism was identified as diffusion of intrinsic Li ion. The room-temperature dielectric constant and loss factor were found to increase with increase in LiCO addition from 160 to 690 and 0.02 to 0.04, respectively. The electrical conductivity was found to increase two orders of magnitude (10-10 Ω cm) in LiCO-added samples as compared to stoichiometric composition. The results obtained here give a strong evidence of the stoichiometry-microstructure and electrical properties correlation, thus emphasizing on the importance of processing parameters to tune the desired properties in LiNaNbO ceramics. [ABSTRACT FROM AUTHOR]