When near-infrared fluorescence meets supramolecular coordination complexes: Challenges and opportunities of metallacycles/metallacages in precision biomedicine

•Supramolecular coordination complexes have made incredible strides in biomedical applications in recent years.•Through modulating the building blocks, the photophysical properties of supramolecular coordination complexes could be finely tuned.•The NIR bio-window provides more accurate imaging and photo-treatment option compared with traditional ultraviolet-visible region.