We report on the synthesis, physico-chemical properties of magnesium sulfanyl porphyrazine derivatives with peripheral hyperbranched groups and their deposition on the multi-walled carbon nanotube surface. Sulfanyl porphyrazines containing bulky and dendrimeric peripheral benzyloxy units, mers, up to their second generation, were synthesized and characterized using MS, UV–Vis, FT-IR, NMR spectroscopy and HPLC. The morphology of the hybrid nanostructures was researched using SEM and AFM microscopy. Their potential for biomedicine and technology was assessed in an electrochemical study. The electrodes modified with dendrimeric sulfanyl porphyrazine/multiwalled carbon nanotube hybrids were utilized for electrocatalytic determination of hydrogen peroxide, which is an important compound generated in many enzymatic reactions. The strong synergistic effect between two nanostructural components, namely multi-walled carbon nanotubes and dendrimeric porphyrazines was evaluated in the electrochemical study. In the result a significant enhancement of electrochemical properties of the modified electrode was observed. The reversible redox couples derived from porphyrazine ring–based electron transfer were responsible for the improvement of the electrocatalytic response of the modified electrode toward hydrogen peroxide reduction. According to the electrochemical results, multi-walled carbon nanotube - dendrimeric porphyrazine hybrids deposited on the surface of glassy carbon electrode constitute a valuable material for enzyme–free biosensor development.