The photophysical properties of porphyrins with N3S and N3O cores appended with two boron-dipyrrin units and porphyrins with N2S2 and N-4 cores appended with four boron-dipyrrin units are described. The steady-state fluorescence measurements indicate that the energy transfer from boron-dipyrrin units to the porphyrin unit is efficient with N-4 and N3O porphyrin cores and less efficient with N3S and N2S2 cores. The energy transfer rates calculated from lifetime measurements are also in support with these observations. (C) 2004 Elsevier B.V. All rights reserved.