In the title complex, [Pt(C15H11N4O)Cl3]·CH3CN, the PtIV ion adopts a distorted octahedral coordination geometry defined by a tridentate cyclometalated NCN ligand and three Cl atoms. In the crystal, individual molecules are aggregated into a three-dimensional network by C—H⋯Cl hydrogen-bonding interactions and π–π stacking interactions between the tridentate ligands, the shortest ring centroid–centroid distance being 3.613 Å.