Edited by Haruki NakamuraBioinorganic species play essential roles in living organisms. Figure 1 shows the elements found in living things so far, and most of them are known as essential elements for human beings [1]. In particular, the concentrations of the inorganic species must be controlled within each appropriate range because the dysfunctions of the homeostasis of inorganic species often cause diseases. Revealing the relationship between the dysfunction of inorganic species' homeostasis and diseases must lead to the development of new drugs for the treatment of the diseases such as cancer and neurodegenerative diseases. Live-cell imaging is a powerful method to investigate the alteration of inorganic species in living cells and has contributed to elucidating the roles and functions of inorganic species in living systems. We organized the symposium, "Live-cell Imaging of Bio-metal Species," at the 60th Annual Meeting of the Biophysical Society of Japan to introduce recent advances in imaging technologies for metal ions and inorganic species. This symposium is co-supported by Scientific Research on Innovative Areas, "Integrated Bio-metal Science" [2]. One of the ultimate goals of this area is to decipher the behaviors of bioinorganic species from whole organisms to molecular levels. In this context, cutting-edge methods to visualize bioinorganic species are required. In this symposium, we invited six upcoming researchers working on imaging of inorganic species to present their recent achievements.Dr. Hirayama reported a Fe (II)-selective fluorescent probe and a heme-selective fluorescent probe. Iron is the most abundant transition metal in our body and is involved in various physiological activities such as oxygen transport and energy production. At the same time, its high redox activity triggers oxidative stress when an iron overload occurs. Thus, as in the case of other metal species, iron status must be controlled within an appropriate level. RhoNox-4, the most sensitive and robust fluorescent probe for labile Fe (II) ever, was presented [3]. The probe was applied to high-throughput screening (HTS) of compounds that fluctuate subcellular iron status. He also presented the development of a hemeselective fluorescent probe and its application to live-cell imaging. Heme is also essential chemical species to almost all living organisms, but its cellular trafficking remains unknown. The probe is highly sensitive and selective to heme and succeeded in visualizing the upregulation of labile heme during ferroptosis [4].Dr. Kowada presented organelle-specific quantitative imaging of Zn (II) with their unique Zn (II) fluorescent probes fused with a HaloTag ligand. Zinc is the second most abundant transition metal ion and acts as a signaling mediator and enzyme cofactor. The concentrations of Zn (II) vary from organelle to organelle, and alterations in Zn (II) concentrations have been a target of interest to many researchers. In this symposium, organelle-specific Zn (II) fluorescent probes were presented to establish ...