1：Experimental Design and Method Selection:

The study involved synthesizing a series of indolizine-cyanine dyes with different anions (Cl-, NO3-, ClO4-, PF6-, TFSI, TPB, BARF) via salt metathesis reactions. Computational analysis using Gaussian 09 and WebMO was performed to determine anion volumes, electrostatic surface potentials, and Mulliken charges. Photophysical properties (absorption, emission, quantum yields) were measured in solvents (acetonitrile and dichloromethane) and as thin films using UV-Vis-NIR spectroscopy and emission spectroscopy.

2：Sample Selection and Data Sources:

Dyes were synthesized starting from C5-ClO4, with anions selected based on size and charge distribution. Samples were purified using column chromatography and characterized by NMR and HRMS.

3：List of Experimental Equipment and Materials:

Equipment included UV-Vis-NIR spectrometer (Cary 5000), NMR spectrometers (Bruker Avance-300 and -500), spin coater (Laurell Technologies WS-650MZ-23NPPB), emission spectrometer (Horiba LabRam), and computational software (Gaussian 09, WebMO). Materials included solvents, salts for metathesis, and silica gel for purification.

4：Experimental Procedures and Operational Workflow:

Dyes were synthesized via metathesis reactions, purified, and dissolved in solvents for optical measurements. Thin films were prepared by spin coating. Absorption and emission spectra were recorded, and quantum yields were calculated relative to a standard (indocyanine green).

5：Data Analysis Methods:

Data were analyzed using computational methods for anion properties and spectroscopic techniques for optical properties. Statistical analysis included comparison of molar absorptivities, Stokes shifts, and quantum yields across different anions and solvents.