This is a minireview about the roles of Cu, Fe, Mn and Zn in plant photosynthesis and finally there is a very short part on artificial leaves with Ni. The role of the transition metals in biology amazes me. They are so important that deficiency or higher concentrations of these metal ions have detrimental effects on the plants' or other living organisms' lives. Sometimes I think that some metal ions have very similar ionic radii and in fact it should not be a huge problem to have one instead of another. But, when you look at the biology you see only one ion instead of the other. How is this regulated? What brings those metal ions and places them in those proteins or organelles? Yes, there are chaperones but what is the source of this incredibly high selectivity and how are they transported? I hope one day we will learn.