Diamond is the host for more than 500 optically active defects. Some of them represent significant interest not only in jewelry but also in quantum technologies. For instance, nitrogen-vacancy center was extensively studied over the last two decades because of its potential applications in sensing and quantum information processing. However, the poor optical properties of this defect limit construction of the scalable quantum registers or quantum networks. Recently emerged new family of diamond defects based on group-IV elements demonstrate superior optical characteristics and keep a promise to become a new platform for the realization of quantum networks. In this talk, I will discuss optical and spin properties of the group-IV defects, show recent progress in fabrication, studies, and application. I will also outline our approach combining long-lasting memory with the nearly ideal optical interface.