Two new strontium gallium nitrides were obtained as single crystals by reaction in molten Na. Black Sr3GaN3 is isostructural with its transition metal analogues, Sr3MnN3, Ba3MnN3, Sr3CrN3, Ba3CrN3, and Ba3FeN3, and is the first example of a 313-ternary nitride containing only main group metals. It crystallizes in space group P6(3)/m (No. 176) with a = 7.584(2) Angstrom, c = 5.410(3) Angstrom, and Z = 2. Black Sr6GaN5 is isostructural with Ca6GaN5 and also with its transition metal analogues, Ca6MnN5 and Ca6FeN5. It crystallizes in space group P6(3)/mcm (No. 193) with a = 6.6667(6) Angstrom, c = 12.9999(17) Angstrom, and Z= 2. Both Ga compounds contain isolated planar [GaN3](6-) nitridometallate anions of D-3h symmetry.