The　electron-deficient　naphthalene　diimides　(NDIs)　are　ideal　π-Lewis　acid　dyes　for　studies　of　lone　pair-π　interactions　but　remain　unexplored.　By　a　crystal　engineering　approach,　herein　we　report　that　lone　pair-π　interactions　between　C　=　O　and　π-acceptors　indeed　have　been　found　not　only　in　free　NDIs　but　also　in　their　coordination　networks.　Interestingly,　the　lone　pair-π　interactions　between　C　=　O　in　the　including　solvents　and　NDIs　are　stronger　than　those　found　in　the　own　C　=　O　of　imides,　but　weaker　than　the　hydrogen-bonding　interactions　between　solvent　C　=　O　and　H-acceptors.　In　addition,　the　coordination　by　metal　cation,　the　directionality　and　number　of　the　lone-pair-bearing　molecules　play　a　crucial　role　on　the　lone-pair-π-interaction　strength.　These　findings　are　undoubtedly　of　considerable　significance　for　the　development　of　NDI　catalytic　materials.　©　2014　©　2014　Taylor　&　Francis.