[en] Radioactive labelling of guanidine-bearing tetraphenylporphyrin and Dy-texaphyrin with selected radionuclides (¹⁶⁶Ho and ⁹⁰Y) is described. A basic characterisation of studied porphyrin and texaphyrin, including their behaviour in a wide range of pH values and data on holmium and yttrium complexation with these compounds was probed using UV-VIS absorption spectrometry. The labelling yield of these macrocyclic molecules depends on the pH of the reaction mixture, metal:ligand ratio and time of incubation. Optimal reaction conditions for formation of porphyrin and texaphyrin radioactive complexes were determined by thin layer chromatography with the detection of β^- activity. The ability of porphyrin derivatives to bind anions was examined as well. Our experiments were focused on perrhenate ion (ReO₄^-) because radiopharmaceuticals labelled with isotopes ¹⁸⁶Re and ¹⁸⁸Re play an important role in therapy of numerous tumour diseases. The possibility of applying ReO₄^- anion directly for labelling purposes, without the necessity of its reduction to lower oxidation state, was not proved. (author)