Birefringent　materials　play　a　crucial　role　in　advanced　applications　such　as　nonlinear　optics,　high-density　data　storage,　and　display　technologies.　Three　birefringent　compounds,　P4S3　(1),　P4S5　(2),　and　P4S7　(3),　are　studied,　all　exhibiting　broad　transmission　in　the　range　of　approximate　to　0.38-14　mu　m,　with　remarkable　birefringence　values　of　0.178,　0.173,　and　0.194　@546　nm,　respectively,　surpassing　that　of　commercial　alpha-BaB2O4　(0.124　@546　nm).　The　relationships　between　their　topological　atomic　and　bonding　properties　and　birefringent　performance　are　established　by　high-resolution　experimental　charge　density.　The　unusual　phenomenon　of　considerable　differences　in　single　molecule　polarizability　anisotropy　among　1-3,　despite　their　similar　crystal　birefringence,　can　be　attributed　to　3D　aromaticity　and　packing　effects,　which　induce　enhanced　electron　delocalization　and　directional　noncovalent　pi-pi　interactions,　unprecedently　in　the　field　of　birefringent　materials.　This　work　provides　valuable　insights　for　the　design　of　new　birefringent　materials　by　leveraging　packing　effects　to　induce　favorable　charge　density　characteristics.