[2,1]-Azaboranaphthalenes represent unique boron–nitrogen (BN) isosteres of naphthalenes. Now a modular approach to the three-component synthesis of BN-2,1-azaboranaphthalene has been developed using TMSN3 as an exogenous nitrogen source. The method proceeds under mild conditions and enables a regioselective incorporation of carbon and nitrogen atoms, showcasing broad potential for the synthesis of BN-based scaffolds.