Single crystals of AgGaGeS4 (AGGS) were grown in a modified Bridgman furnace with 25 mm in diameter and 70mm in length. The transmission spectra of as-grown AGGS slices were measured on a Hitachi 270 - 30 spectrophotometer, the fabricated device crystal was 5 mm×5mm×3.5 mm in dimension and its absorption was 0.04-0.15 cm-1. Frequency doubling of 2.79 and 8 μm laser radiation were investigated using fabricated device crystals with thicknesses of 3.5 and 2.7 mm respectively.