Five Bonds to Carbon through Tri-Coordination in 
 Al3C3−/0

Here, five bonds to carbon through tri-coordination are theoretically established in the global minimum energy isomers of Al3C3− anion (1a) and Al3C3 neutral (1n) for first time. Various Al3C3−/0 identified using density functional theory at PBE0-D3/def2-TZVP level. Chemical bonding features thoroughly analyzed these two (1a 1n) with different topological quantum chemical tools, such as adaptive natural partitioning (AdNDP), Wiberg Bond Indices (WBIs), nucleus-independent shifts (NICS), atoms molecules (AIM) analyses. The structure isomer 1a is planar C2v symmetry, whereas its counterpart 1n non-planar C2 which terminal aluminum out plane. central allenic atom exhibits thus makes it a case carbon, confirmed their total bond order observed WBI. Both show σ- π-aromaticity predicted NICS AdNDP Further, results ab initio molecular dynamics simulations reveal kinetic stability room temperature; thus, they experimentally viable systems.