A versatile luminescence spectrophotometer has been designed and constructed. With this instrument, corrected excitation and emission spectra are recorded automatically in either relative energy or quantum units without loss of resolution or sensitivity. Quantum efficiencies of luminescence are determined directly or by comparison of unknowns with a compound of known quantum efficiency. The instrument covers the spectral range 200-1250 μ with interchangeable gratings and detectors. Low-temperature measurements of fluorescence and phosphorescence are made using aquartz Dewar. Luminescence decay curves are measured to rates approaching 1 msec. High-resolution spectra can be obtained: to ˜ 2 Å between 200 and 750 mμ, and ˜ 10 Å between 750 and 1250 mμ The sample chamber is adaptable to allow for measurement of luminescence of solutions, frozen solutions, solid matrices, crystals, etc. The utility of the instrument for most of these uses is demonstrated.