A series of free-base, zinc and mixed free-base-zinc porphyrin dimers were investigated using electrochemistry, electronic absorption, resonance Raman and emission studies. The spectroelectrochemistry of these compounds was also examined. The electronic absorption and resonance Raman data suggest that the two porphyrins in the dimer are behaving as independent chromophores with limited communication. However, emission studies show that energy transfer occurs between the two units. The linking unit is seen to have limited influence on the properties of chromophores. Copyright (C) 2000 John Wiley and Sons, Ltd.