Fluorescence is a highly sensitive technique that offers many advantages for bioanalysis-a broad area of research that ranges from diagnostic assays to cellular labeling and imaging, to elucidating the interactions of biological systems with one another or abiotic systems. Non- traditional materials such as semiconductor “quantum dot” nanocrystals offer both extra value and novel capabilities in fluorescence-based assays and imaging. This presentation will describe our recent efforts to develop bioassays and bioprobes, in various formats, utilizing the unique physical and optical properties of quantum dots (QDs), often in combination with Förster resonance energy transfer (FRET). QDs offer superior brightness, spectrally broad absorption and narrow emission, and surface area amenable to (bio)chemical modification while retaining molecule-like diffusion. Using proteolysis and peptide-QD conjugates as model systems, we show that these properties uniquely enable (i) promising point-of-care diagnostic formats that utilize mass-produced consumer electronics such as smartphones for readout; (ii) multifunctional probes that can detect the activity multiple proteases as a single vector, or distinguish between protease activity and concentration; and (iii) probes for protease activity that have enhanced and tunable sensitivity and selectivity. Overall, the use of QDs in bioanalysis offers exciting new opportunities that stand to impact several areas of research, helping to build fundamental knowledge and develop new methods that will ultimately improve health care.