1：Experimental Design and Method Selection:

The study combined synthesis, steady-state and time-resolved spectroscopy, and quantum-chemical calculations (TD-DFT) to explore photophysical properties. Synthesis followed a three-step Horner-Wittig method under argon. Spectroscopy included absorption, emission, fluorescence quantum yield, and lifetime measurements. Computational methods used DFT and TD-DFT with M06-2X functional and Polarizable Continuum Model for solvent effects.

2：Sample Selection and Data Sources:

Six thiophene derivatives (BT-Th-oNO2, BT-Th-mNO2, BT-Th-pNO2, BT-Th-oCN, BT-Th-mCN, BT-Th-pCN) were synthesized and characterized. Solutions in chloroform (c = 2.40 x 10^-5 M) were used for photophysical measurements. Reference for quantum yield was fluorescein in ethanol.

3：40 x 10^-5 M) were used for photophysical measurements. Reference for quantum yield was fluorescein in ethanol. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Bruker 300 MHz NMR spectrometer, Bruker Vertex 70 IR spectrometer, Jeol JMS 700 high-resolution mass spectrometer, Shimadzu UV 1800 Spectrometer, Shimadzu RF-6000 Spectrofluorometer, PicoQuant HydraHarp 400, PicoQuant LDH-P-C-405B diode laser, SpectraPhysics MaiTai Ti:Sapphire oscillator, Acton Research SpectraPro 150 monochromator, Hamamatsu R3809U-50 photomultiplier, Ortec Model 9327 amplifier, BBO crystal, quartz cuvettes. Materials included chloroform, ethanol, fluorescein, titanium dioxide, and reagents from Sigma Aldrich.

4：Experimental Procedures and Operational Workflow:

Synthesis involved Horner-Wittig reactions under argon. Photophysical measurements: absorption spectra in quartz cuvettes, emission spectra with spectrofluorometer, quantum yield by relative method, fluorescence lifetimes with laser excitation (405 nm) and detection at magic angle. Computational procedures: geometry optimization and frequency calculations with M06-2X/6-31G(d), transition energies with 6-311+G(2d,p), charge-transfer parameters using Le Bahers approach.

5：Data Analysis Methods:

Fluorescence quantum yield calculated using equation (1). Fluorescence lifetimes fitted with multiexponential decay functions using DecayFit 1.4 software. Radiative and non-radiative rate constants derived from equations (3) and (4). Quantum-chemical data analyzed with Gaussian16.