Bioimaging is a vital tool in the fields of biology and medicine. Among the various imaging methods available for clinical use and in research, such as radiation-based or magnetic resonance imaging, optical imaging is a highly complementary technique due to the possibility to acquire data at high speed and to detect dynamic processes. Seeking deep-tissue optical imaging at high spatial resolution, the ability of the applied light to penetrate the biological tissue is a most significant parameter. In this context, the near-infrared (NIR) region from 700 to 1870 has clearly been identified as the wavelength region of choice. Yet, the development of advanced biocompatible probes showing bright NIR emission under NIR excitation is crucial in order to bring optical deep-tissue imaging to the next level, and cutting-edge research is conducted around the world focussing on novel optical probes, including lanthanide-doped inorganic nanostructures, single-wall carbon nanotubes, and innovative quantum dots (QDs). Beyond optical techniques, the concept of multimodality is receiving increasing attention given that multimodal imaging is a powerful tool combing the advantages of several imaging methods (e.g. optical, MRI, CT, ultrasound, PET, SPECT) while overcoming their individual intrinsic limitations. Addressing this trend, it is the particular aim of this symposium to bring together experts from different fields to foster interdisciplinary exchange eventually resulting in more powerful tools. Major (yet not the sole) focus will be set on the application oriented design of novel probe materials seeking deep-tissue high resolution imaging, improved biocompatibility, smart assembly of multiple functionalities in one multimodular nanocarrier resulting in more reliable theranostic or sensing tools and better understanding of nano-bio-interactions, as well as improved targeting capabilities and controlled biodistribution when seeking in-vivo application. Thus, the goal of this symposium is to present and discuss the most recent achievements, trends, and remaining challenges regarding advanced probe design, characterization and in-vitro / in-vivo application.