New symmetrically para-substituted tetraphenylporphyrin Tl(III) salicylate complexes, having the general formula SA/5-SSATl(III)t(4-Y)PP (Y = -H, -CH 3 , -OCH 3 ); SA = salicylates and 5-SSA = 5-sulfosalicylates, were synthesized and characterized by elemental analysis, optical absorption/emission studies, infrared spectrum, NMR studies ( 1 H, 205 Tl), thermal analysis and mass spectra; the complexes are in good consistency with experimental results. All the newly synthesized complexes exhibited good optical property, and thermogravimetric analysis (TGA) results showed their excellent thermal stability ( > 400°C). Macrocyclic complexes of Tl(III) ligate to axial ligand to form six-coordinate complex, the nature of which influences the photophysical properties of the former depending upon the spin-orbital coupling character of the axial ligand. A square-based pyramidal structure has been proposed on the basis of these studies. In addition, some of the synthesized complexes of thallium porphyrins were also screened for anti-bacterial activity. Cytotoxic activity of 5-SSATl(III)t (4-OCH 3 )PP evaluated against four human cancer cell lines exhibited strong (up to 90%) growth inhibition.