Objective. This work investigates the use of Al₂O₃:C and Al₂O₃:C,Mg optically stimulated luminescence (OSL) detectors to determine both the dose and the radiation quality in light ion beams. The radiation quality is here expressed through either the linear energy transfer (LET) or the closely related metric Q _eff, which depends on the particle’s speed and effective charge. The derived LET and Q _eff values are applied to improve the dosimetry in light ion beams. Approach. OSL detectors were irradiated in mono-energetic ¹H-, ⁴He-, ¹²C-, and ¹⁶O-ion beams. The OSL signal is associated with two emission bands that were separated using a pulsed stimulation technique and subjected to automatic corrections based on reference irradiations. Each emission band was investigated independently for dosimetry, and the ratio of the two emission intensities was parameterized as a function of fluence- and dose-averaged LET, as well as Q _eff. The determined radiation quality was subsequently applied to correct the dose for ionization quenching. Main results. For both materials, the Q _eff determinations in ¹H- and ⁴He-ion beams are within 5 % of the Monte Carlo simulated values. Using the determined radiation quality metrics to correct the nonlinear (ionization quenched) detector response leads to doses within 2 % of the reference doses. Significance. Al₂O₃:C and Al₂O₃:C,Mg OSL detectors are applicable for dosimetry and radiation quality estimations in ¹H- and ⁴He-ions. Only Al₂O₃:C,Mg shows promising results for dosimetry in ¹²C-ions. Across both materials and the investigated ions, the estimated Q _eff values were less sensitive to the ion types than the estimated LET values were. The reduced uncertainties suggest new possibilities for simultaneously estimating the physical and biological dose in particle therapy with OSL detectors.