The article explores the existence of Dirac cones in the band structures of two-dimensional carbon materials, specifically graphynes, which are not limited to graphene's hexagonal symmetry. The authors use first-principles electronic structure calculations to investigate three graphynes: α-graphyne, β-graphyne, and 6,6,12-graphyne. They find that α-graphyne and β-graphyne exhibit Dirac cones with different symmetries, while 6,6,12-graphyne, despite having a rectangular symmetry, also shows Dirac cones with direction-dependent properties. These findings suggest that the presence of Dirac cones in two-dimensional materials is not solely dependent on hexagonal symmetry and can occur in materials with various symmetries, potentially leading to unique electronic properties. The study highlights the potential for a wide range of two-dimensional materials with interesting electronic properties, including those made from non-carbon atoms.The article explores the existence of Dirac cones in the band structures of two-dimensional carbon materials, specifically graphynes, which are not limited to graphene's hexagonal symmetry. The authors use first-principles electronic structure calculations to investigate three graphynes: α-graphyne, β-graphyne, and 6,6,12-graphyne. They find that α-graphyne and β-graphyne exhibit Dirac cones with different symmetries, while 6,6,12-graphyne, despite having a rectangular symmetry, also shows Dirac cones with direction-dependent properties. These findings suggest that the presence of Dirac cones in two-dimensional materials is not solely dependent on hexagonal symmetry and can occur in materials with various symmetries, potentially leading to unique electronic properties. The study highlights the potential for a wide range of two-dimensional materials with interesting electronic properties, including those made from non-carbon atoms.