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We have synthesized single crystals of Dirac semimetal candidates with and Sr. In contrast to , the Ba material displays a local Zn vacancy ordering, which makes the observation of quantum oscillations in out-of-plane magnetic fields possible. As a Dirac semimetal candidate, exhibits a small cyclotron electron mass, high quantum mobility, and nontrivial Berry phases. Three Dirac dispersions are observed by angle-resolved photoemission spectroscopy and identified by first-principles band-structure calculations. Compared to systems which host Mn magnetic moments, acts as a nonmagnetic analog to investigate the intrinsic properties of Dirac fermions in this structure family.