Cocrystal 55DMBP-H(2)ba was synthesized and characterized. The crystal structure is isostructural to cocrystal 55DMBP-H(2)ia with iodanilic acid. The heat capacity, dielectric permittivity, and polarization electric field hysteresis showed that the 55DMBP-H(2)ba undergoes a paraelectric-ferroelectic phase transition at 253 K on cooling. The transition mechanism is discussed through the analysis of isotropic temperature factors of atoms.