Azulene, a simple polar polycyclic aromatic hydrocarbon with connected electron donor and acceptor (DA), ignites the hope of designing second‐order nonlinear optical (NLO) molecular materials from pure nonpolar carbon nanomaterials. In this work, a butterfly‐shaped nanographene (π−DA−π) was designed by incorporating azulene between two coronenes. One more electron in a N atom or one electron fewer in a B atom with respect to a C atom can polarize charge distribution in carbon nanomaterials, and further doping of B and N in the designed butterfly‐shaped nanographene changes the system from π−DA−π to D−π−A, leading to strong NLO responses. For example, the largest static first hyperpolarizability even reaches 173.89×10−30 esu per heavy atom. The synergetic role of B, N and azulene in the nanographene is scrutinized, and such a doping strategy is found to provide an effective means for the design of carbon‐based functional materials. The strong second‐order NLO responses of these butterfly‐shaped carbon‐based nanographenes under external fields, for example, sum frequency generation and difference frequency generation, could inspire future experimental exploration.