p ‐Block Catecholates: A Century‐Old Platform for Hybrid Molecular Ferroelectrics

ABSTRACT p ‐Block catecholato complexes are known for their robustness, structural diversity, and high synthetic modularity, yet their potential as functional electronic materials has remained unexplored. In this study, we investigate p ‐block catecholato complexes as molecular ferroelectrics for the first time. A series of germanium catecholato salts, [Bu 4 N][Cl‐Ge(cat) 2 ] , [Pr 4 N][Cl‐Ge(cat) 2 ] , and [Et 4 N][Cl‐Ge(cat) 2 ] , was synthesized to assess the influence of counter‐cation size on crystal symmetry and polar order. Single‐crystal x‐ray diffraction reveals a counter‐cation‐dependent transition from centrosymmetric to polar packing, while second‐harmonic generation confirms the noncentrosymmetric nature of [Et 4 N][Cl‐Ge(cat) 2 ] at 290 K. Dielectric spectroscopy, capacitance‐voltage measurements, and double‐wave electrical measurements support switchable polarization in thin films. Piezoresponse force microscopy reveals characteristic amplitude butterfly loops and phase hysteresis, further corroborating reversible piezoelectric switching. These findings establish p ‐block catecholato complexes as a chemically programmable platform for counter‐cation‐controlled hybrid molecular ferroelectrics.