In 2017 two materials were reported -RM734 and DIO -that are now understood to have polar nematic order and are ferroelectric, over a century after Born's conjecture. This so-called ferroelectric nematic (NF) phase displays a slew of unique properties: ferroelectric properties with huge spontaneous polarisation, giant dielectric anisotropy, polar domains, 10 strong non-linear optical response, unique electrooptic responses, and thermal gradient-induced circular motion of particles, to name a few. The remarkable properties of the NF phase, coupled with fluidity and relative ease of alignment , will ensure this field flourishes in the decades to come. Progress in understanding and exploiting the unique physics of the NF phase is reliant on the design and synthesis of new materials, an area that has undergone significant progress in the since the report of the first polar nematic materials in 2017, and this is the focus of this article.