1：Experimental Design and Method Selection:

The study involved the synthesis of a new organic–inorganic hybrid ferroelectric (C4H9NH3)2PbCl4 (1) with a 2D layered perovskite architecture. The methodology included thermal analysis, dielectric measurements, polarization–electric field (P–E) hysteresis loop measurements, variable-temperature single-crystal structure determinations, and photoluminescence studies.

2：Sample Selection and Data Sources:

Crystals of 1 were prepared by slow evaporation of hydrochloric solutions with Pb(CH3COO)2·3H2O and n-butylaminium chloride in a stoichiometric ratio at room temperature.

3：List of Experimental Equipment and Materials:

Differential scanning calorimetry (DSC) for thermal analysis, Radiant Precision Premier II for ferroelectric measurements, TH2828 Precision LCR Meter for dielectric experiments, Keithley 6517B for pyroelectric property measurement, SuperNova diffractometer for variable-temperature X-ray single crystal diffraction experiments, and Edinburgh Instrument FLS980 spectrofluorimeter for fluorescent analyses.

4：Experimental Procedures and Operational Workflow:

The synthesis of 1, followed by characterization using DSC, dielectric measurements, P–E hysteresis loop measurements, SHG measurements, and photoluminescence studies.

5：Data Analysis Methods:

Structural analyses were performed using SHELXS-97 and SHELXL-97 software packages. Photoluminescence data were analyzed for emission spectra, CIE chromaticity coordinates, and color rendering index.