In recent decades, polar intermetallic compounds, particularly those including group 1-3 metals, late transition metals and the p-block elements have been intensively explored. This group of compounds is situated between Hume-Rothery phases and Zintl compounds 5 that is well known for enormous structural diversity and complexity. In contrast to both where essential rules of formation and classification are well established, such mechanisms in polar intermetallics, though including some features from the former, are not completely understood. These compounds show high coordination numbers for the largest elements (up to 24), including elements with considerable differences in electronegativity but still keep metallic conductivity in contrast to semiconducting Zintl phases.