Аннотация:In this Special Issue, different aspects of multifunctional borate crystals are discussed: from ortho- and oxyorthoborates to compounds with condensed anions and from their nonlinear optical and laser properties to piezoelectric characteristics. For this reason, complex investigations of phase relationships in multi-component borate melts, study of crystal growth conditions of novel high-temperature borates and development of the “crystallization conditions-composition-structure-properties” concept will provide a scientific base for growth technologies of high performance electronic and optical devices and components with a variety of industrial, medical and many other applications. In the meantime, these relationships can help to estimate an affinity of synthetic borate materials with their natural prototypes and structural analogues.