  We demonstrate that ethylammonium copper chloride, (C2H5NH3)2CuCl4, a member
of the hybrid perovskite family is an electrically polar and magnetic compound
with dielectric anomaly around the Curie point (247 K). We have found large
spontaneous electric polarization below this point accompanied with a color
change in the sample. The system is also ferroelectric, with large remnant
polarization (37{\mu}C/cm2) that is comparable to classical ferroelectric
compounds. The results are ascribed to hydrogen-bond ordering of the organic
chains. The coexistence of ferroelectricity and dominant ferromagnetic
interactions allows to relate the sample to a rare group of magnetic
multiferroic compounds. In such hybrid perovskites the underlying hydrogen
bonding of easily tunable organic building blocks in combination with the 3d
transition-metal layers offers an emerging pathway to engineer multifuctional
multiferroics.
