This work employs UV/vis absorption and Z-scan techniques to investigate how the presence of one or two halogens atoms and the macrocycle protonation affect the photophysical characteristics of sulfonated porphyrins. The results are relevant to photomedicine and photonics because they show that: (i) the insertion of halogen atoms increases the intersystem crossing quantum yield, a useful feature for photodynamic therapy, (ii) the fluorescence observed in fluorinated porphyrins shows desired characteristics for theranostics, which combine therapy and diagnostics in the same platform, and (iii) the protonation enhances the excited-state absorption in the visible region, an important feature for optical limiting. (C) 2015 Elsevier B.V. All rights reserved.