The luminescence of covalently linked "triad" compounds X-P-Y have been studied in DMF and benzene solutions.It is found that the attachment of sub-stituent X=CI

CH

3

O-as well as Y=phenyl(B)and nitrophenyl group(NB)has no detectable effect on both absorption and luminescencs spectra of the central porphyrin P

although a little solvent-dependent shift in their maximum frequency is observed.The substitutions

however

lead to a change in the luminescence intensity

particularly that of vibronic band.In these cases

the luminescence of Cl-attached P-B compounds is always more intense as compared with the rompounds with CH

3

O substituent as the X moiety.The replacement of phenyl substituent by nitrophenyl in Y moiety of compounds CH

3

O-P-Y leads to an enhancement of their luminescence

but the opposite trend is observed in the Cl-substitued compounds Cl-P-Y upon the same structural change in Y substituent.In both cases

the substitution of-NO

2

at ortho position of phenyl ring of substituent Y shows again so-called "Ortho effeect" at we reported previously in compounds of nitroporphyrins.These pictures are the same in both polar and apolar solvents and seem to be understandable by a tentative assumption that the luminescence intensity of these compounds is regularly coorelated to the substitution-induced shift of eletron density in the electronic system of porphyrin macrocycle.Thus

it is believed that these findings reported here will offer some hint leading to improve our scientific knowledge for an ingenious design of artificial molecular system for utilization of solar energy with high efficiency.