We report on the single-crystal growth and basic optical and electrical properties of a new quaternary compound AgCd2GaS4. Single crystals of AgCd2GaS4 were grown using a solution-melt technique. The spectral distribution of absorption, luminescence, photoconductivity, as well as excitation spectra and electrical conductivity were investigated. Because of high photosensitivity, intense luminescence, wide transparency range together with expected high laser damage threshold, AgCd2GaS4 crystals are promising electro-optical materials. (c) 2005 Elsevier B.V. All rights reserved.