1：Experimental Design and Method Selection:

The study involved designing and synthesizing three BOPIM complexes (T1, T2, T3) with different substituents (bromo, tert-butyl, methoxyl) to investigate their optical properties and mechanofluorochromic (MFC) behaviors. Methods included synthesis via multi-component one-pot reactions and boron chelation, characterization using NMR, FT-IR, mass spectrometry, UV-vis absorption, fluorescence emission spectra, quantum chemical calculations (DFT), X-ray diffraction, powder XRD, and DSC.

2：Sample Selection and Data Sources:

Samples were the synthesized BOPIM complexes T1, T2, and T3. Data sources included spectroscopic measurements in various solvents and solid states, single crystal data for T1, and computational data from Gaussian 09W.

3：Data sources included spectroscopic measurements in various solvents and solid states, single crystal data for T1, and computational data from Gaussian 09W. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Bruker AMX-400 NMR spectrometer, Nicolet-360 FT-IR spectrometer, Agilent 6500 Q-TOF mass spectrometer, Beijing purkinje TU-1810 Spectrophotometer, Shimadzu RF-5301 PC Spectrofluorophotometer, Edinburgh FLS920 steady state spectrometer, Bruker Advances D8 X-ray diffractometer, Mettler Toledo 3 thermos system, Rigaku RAXIS-RAPID diffractometer. Materials included 2-cyanopyridine, aromatic aldehydes, NH4OAc, BF3·Et2O, solvents (e.g., CH2Cl2, THF, DMF), and silica gel for chromatography.

4：Experimental Procedures and Operational Workflow:

Synthesis involved reacting 2-cyanopyridine with aldehydes and NH4OAc to form ligands L1-L3, followed by chelation with BF3·Et2O to form T1-T3. Purification used column chromatography and recrystallization. Optical properties were measured in solutions and solid states. MFC behaviors were tested by grinding powders with a pestle and mortar and fuming with DCM. Reversibility was checked by repeated grinding and fuming.

5：Purification used column chromatography and recrystallization. Optical properties were measured in solutions and solid states. MFC behaviors were tested by grinding powders with a pestle and mortar and fuming with DCM. Reversibility was checked by repeated grinding and fuming. Data Analysis Methods:

5. Data Analysis Methods: Data analysis included comparing UV-vis and fluorescence spectra, calculating quantum yields, performing DFT calculations for HOMO-LUMO and energy gaps, analyzing X-ray and PXRD patterns for crystal structure and phase changes, and DSC for thermal properties.