1：Experimental Design and Method Selection:

The study involved synthesizing and characterizing chloroindium(III) complexes of tetra(4-methylthiophenyl)porphyrin (2a) and tetra-2-thienylporphyrin (2b), conjugating 2a with gold nanoparticles (AuNPs), and evaluating their photophysicochemical properties, dark cytotoxicity, and PDT activity against MCF-7 breast cancer cells. Theoretical calculations using Gaussian 09 with B3LYP and CAM-B3LYP functionals were employed for electronic structure analysis.

2：Sample Selection and Data Sources:

The MCF-7 epithelial breast cancer cell line was used for in vitro studies. Dyes and conjugates were tested over a concentration range of 3.0–40 μg/mL.

3：0–40 μg/mL. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Instruments included a Bruker AutoFLEX III MALDI-TOF mass spectrometer, Vario EL III CHNS Analyzer, Bruker AVANCE II 600 MHz NMR spectrometer, Bruker D8 Discover diffractometer, Shimadzu UV-2550 spectrophotometer, Varian Eclipse spectrofluorimeter, Picoquant FluoTime 300 TCSPC setup, Zeiss Libra TEM, Chirascan plus spectrodichrometer, Modulight 7710-680 Medical Laser with Thorlab M625L3 LED, Coherent FieldmaxII TOP energy/power meter, Zeiss AxioVert.A1 Fluorescence LED inverted microscope, and BioTek Synergy 2 microplate reader. Materials included various chemicals from Sigma-Aldrich, Merck, Cellonex, Biowest, and Lonza.

4：Experimental Procedures and Operational Workflow:

Synthesis of dyes and conjugates followed literature methods. Photophysical parameters (fluorescence and singlet oxygen quantum yields) were measured using comparative methods with standards. In vitro studies involved cell culturing, drug administration, irradiation (10 min at 625 nm), and viability assessment using WST-1 assay. Data were analyzed statistically with ANOVA.

5：Data Analysis Methods:

Fluorescence quantum yields were determined comparatively using ZnTPP as standard. Singlet oxygen quantum yields were measured with DPBF as quencher and Rose Bengal as standard. Cell viability was calculated from absorbance ratios at 450 nm.