Each center has also pioneered a diverse collection of diagnostic technologies based on the fundamental principles of tissue spectroscopy and imaging. Optical diagnostics are well suited for noninvasive and minimally invasive, point-of-care medicine. The current medical photonics diagnostic market is primarily based on optical endoscopy, microscopy, near-infrared tissue/pulse oximetry, perfusion/flow imaging, and OCT. The field of biophotonics and biomedical optics has been dominated by remarkable advances in these and related devices over the past . Factors, such as miniaturization, reductions in barriers-to-access, and the changing healthcare landscape, will further accelerate the growth and commercialization of diagnostic medical photonics. In addition, multimodality and hybrid approaches, spanning from “optics + ultrasound” to “optics + MRI” are rapidly expanding and expected to achieve clinical and commercial success in the coming years. Many of these methods are described in this special issue. BLI, MLL, and WCP have each played a unique role in fostering translation of these methods into medical practice, because of their longstanding commitment to patient outcome and special expertise in identifying new and clinically impactful applications of emerging technologies. Examples include advancing OCT in vascular, pulmonary, GI, and head and neck disease, and using diffuse optics to guide chemotherapy in breast cancer. This is possible, in part, because of each center’s rich portfolio and well-established infrastructure that supports time and effort-intensive translational biophotonics studies. Overall, WCP, BLI, and MLL have a portfolio of more than 50 Institutional Review Board (IRB) protocols in optical diagnostics, and enroll hundreds of patients annually on multiple investigator-initiated hypothesis-based studies.