Imaging is the only medical tool currently capable of non-invasively capturing detailed, real time and spatially resolved biochemical information in vivo and thus delineating disease so that non-invasive curative resection or treatment of the affected area can take place. Though visible and near infrared (NIR) light undergo a wide range of complex interactions in tissue — interactions which can be harnessed to yield useful information about the underlying pathology — optical imaging has yet to be fully utilised in clinic, with many existing techniques relying on standard colour imaging that replicates human vision. This thesis describes my recent effort advancing novel optical endoscopic imaging techniques towards clinical translation. Before embarking on the development of novel devices, an analysis was made of the common challenges in translating optical imaging techniques. Through this work, a streamlined roadmap to clinical translation was developed, and key translational characteristics were defined. These were used to guide subsequent development of endoscopic devices. Initial efforts were focused on the development of flexible endoscopes for detection of dysplasia in Barrett’s oesophagus. To enable molecular imaging with a newly discovered targeted fluorescent contrast agent, a bimodal endoscope capable of capturing NIR fluorescence and white light reflectance was developed around a clinically translatable device architecture, and image artefacts were addressed by developing and evaluating image correction algorithms. This technique demonstrated significant potential for delineation of dysplasia in ex vivo samples. Next, a multispectral endoscope capable of imaging multiple fluorophores or endogenous tissue reflectance was developed. This device was successfully translated to a clinical pilot study, where initial results showed the promising potential of multispectral endoscopy for delineation of dysplasia based on endogenous reflectance from oesophageal tissue. Finally, multispectral imaging was explored for intraoperative delineation of adenoma and healthy pituitary tissue. A novel rigid multispectral endoscope was developed, preliminary technical characterisation of this device was performed, and a clinical pilot study was planned. With continuation of this work as outlined at the end of this thesis, the novel techniques described here have the potential to improve the standard of care in their respective indications.