In the evolving landscape of modern science and technology, the field of polaritonics has emerged as a beacon of innovation and discovery. With its roots grounded in the coherent interplay of light and matter, polaritonics has pushed the boundaries of our understanding of many-body and quantum phenomena, and harnessed their potential for revolutionary applications. We are delighted to introduce this special issue, dedicated to exploring the cutting-edge of polaritonics research and its profound implications for various domains of science.