The present invention provides an optical absorbent and its application. The invention provides the optical absorbent, as an organic optical absorbent, exhibiting excellent compatibility or
solubility in various solvents and resin components, and having excellent
heat resistance thereby providing the optical absorbent capable of stably maintaining optical properties even under high temperature condition or high temperature and
high humidity conditions. The present invention can also provide an optical absorption film that obtains desired optical properties by applying the optical absorbent. The present invention may also provide applications of the optical absorbent or the optical absorption film, and may provide, for example, an
optical filter, a
solid-state image capturing device, and / or an
infrared sensor including the optical absorbent or the optical absorption film.