We report the synthesis, characterization, and scope of a new versatile emissive molecular probe functionalized with a 1,10-phenanthroline moiety containing methylserotonin groups as binding sites for metal ion recognition. The synthesis, characterization, and evaluation of the in vitro imaging capability of the iridium(III) and ruthenium(II) complexes [Ir(ppy)2(N-N)](+) and [Ru(bpy)2(N-N)](2+), in which ppy is 2-phenylpyridine, bpy is 2,2'-bipyridine, and N-N is a 1,10-phenanthroline ligand functionalized with two methylserotonin groups to serve as binding sites for metal ion recognition, is reported. The uptake of these compounds by living freshwater fish (Carassius auratus) was studied by fluorescence microscopy, and the cytotoxicity of ligand N-N and [Ru(bpy)2(N-N)](2+) in this species was also investigated.