Have you ever fantasized about the day when you would simply walk into the doctor’s office, drink a cocktail of “diagnostic juice” and enter an infra-red chamber which would illuminate any signs of disease?To most of us the perspective of diagnostics through molecular imaging is currently unimaginable and one might argue that we are far from witnessing such a dream come true, the technological improvements required and obstacles to overcome being far too great. Yet, the advances in fluorescence imaging technologies, together with the emergence of novel chemical probes, fluorescent biosensors and molecular tracers, and the development of new generations of nanocarriers that are particularly well suited for in vivo applications, are now providing a glimpse of hope.