A series of novel sensing materials with concurrent sensitivity, namely the porphyrins [free-base, Mn(III) and Fe(III) complexes], functionalized with crown-ether or aza-crown (cyclam) pendant groups, were synthesized and tested as ionophores for polymeric membrane electrodes. Several aspects were studied in order to evaluate the functionality and the desired sensitivity of resulting crown-porphyrins hyphenated ionophores, among them the nature and the size of crown fragment cavity, the length of the alkyl pendant incorporating the crown-ether unit, the presence and the nature of central metal ion both in porphyrin and crown macrocycles.