Optical and electrical properties of thermally evaporated lithium borate (LiBO2) films have been studied. This work is especially aimed towards the application of such films as lithium ion conductors (IC) in electrochromic (EC) devices. LiBO2films exhibit a high degree of transmission (over 90%) in the solar spectral range and a lithium ion conductivity of the order of nearly 10−7S cm−1. Hence, such films have a good potential for use as ICs in EC devices.