Polaritons-hybridized light-matter modes involving collective oscillations of polarized quasiparticles in the matter allow light trapped at the nanoscale, deep below the optical wavelength, which results in significantly enhanced light-matter interaction. This unveils diverse classical and quantum phenomena and finds applications in molecular sensing, tunable infrared and terahertz detecting, and sub-diffraction imaging. A roadmap for polaritons has been dramatically enriched by two-dimensional materials that support various types of polaritons, including surface plasmon polaritons supported by carriers in conductors, atomic vibrations (phonon) in polar insulators, excitons in semiconductors, cooper pairs in superconductors, and spin resonances in (anti) ferromagnets, etc. This section focuses on the cutting edge of science and technology in the research fields about excitation, propagation, and manipulation of polaritons in 2D materials and their relevant applications. All of the theoretical calculations, numerical simulations, and experimental works are welcome.