Chinese Optics Letters (COL) invites original articles for a Special Issue on Lithium Niobate Based Photonic Devices to be published in June 25 2021. Lithium niobate (LiNbO3) is a multifunctional crystal with combination of a number of excellent properties, such as electrooptical, acousto-optic, nonlinear optical, piezoelectric, and pyroelectric features. In optics and photonics, the LiNbO3-based devices have been widely applied in various aspects. Typical applications include acoustic- and electro-optic modulators, nonlinear wavelength converters, waveguide amplifiers, and quantum memories. The traditional LiNbO3 based photonic devices are constructed on micro-photonic structures, e.g., optical waveguides. A number of techniques have been utilized to produce low-loss LiNbO3 waveguides towards diverse applications. Recently, thin-film devices based on LiNbO3-On-Insulators (LNOI) technology have emerged as promising candidates due to the on-chip integration and strong confinement of light fields. Exciting LNOI-based devices, such as high speed modulators, highly efficient nonlinear optical elements, or hybrid quantum chips, have been developed through advanced techniques, showing distinguished performance for practical applications. There are continuous interests amid researchers on LiNbO3-based photonic devices and related applications, and a number of research groups are devoted to these interesting works. Regarding to these efforts and achievements, the scope of this special focus, covers all aspects of recent theoretical and experimental research related to LiNbO3–based photonic structures and devices.