Recent Advances in Luminescence of Platinum Complexes in the Near Infrared Second Window

The near infrared (NIR) optical window enables to observe biological tissue noninvasively through photoimaging using luminophores. Particularly, the light in the NIR II region of 1000–1400 nm between strong absorption bands of H 2 O and tissue chromophores is advantageous for photoimaging and phototherapies of deep tissue. Pt complexes possessing the high emission ability and the luminescence tunability are expected to be luminophores for deep imaging and photosensitizers of photodynamic therapy. Herein, the NIR II emission from Pt complexes designed by the strategy of the extension of ligand π conjugation and the aggregation by the Pt–Pt interaction from recent works is reviewed.