The two-dimensional (2D) metal halide hybrid (C$_2$H$_5$NH$_3$)$_2$MnCl$_4$ has been grown by slow evaporation technique at room temperature. The phase-purity and morphology were confirmed using powder X-ray diffraction, scanning electron microscope and high-resolution transmission electron microscopy studies. Optical properties like reflectance and bandgap were determined from UV–visible spectrum. The dielectric properties of the studied compound have been investigated using impedance spectroscopy as a function of frequency for different temperatures from 1 Hz to 1 MHz between 353 and 453 K. The real and imaginary components Z'and Z"of impedance are fitted using an equivalent circuit model, consisted of a series combination of parallel resistance-constant phase elements of grain (Rg||CPEg), resistance-capacitance of grain boundary (Rgb||Cgb) and resistance-capacitance of electrode (Rel||Cel), which reveal the existence of distribution of relaxation times and thermally activated non-Debye-like relaxation. The frequency-dependent AC conductivity is well described by Jonscher’s universal power law, which follows the Arrhenuis relation. The aboveresults indicate the semiconductor behaviour with wide bandgap energy.