Boron dipyrromethene (BODIPY) derivatives 1 and 2 consisting of donor and acceptor units with dual photoresponses to solvent polarity and luminogen aggregation are developed through taking advantage of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) processes. In nonpolar solvents, the locally excited (LE) states of the BODIPY luminogens emit intense green lights. Increasing solvent polarity brings the luminogens from the LE state to the TICT state, causing a large bathochromic shift in the emission color but a dramatic decrease in the emission efficiency. The red emission is greatly boosted by aggregate formation or AIE effect: addition of large amounts of water into the solutions of 1 and 2 in the polar solvents causes the luminogens to aggregate supramolecularly and to emit efficiently. The emission can be enhanced by increasing solvent viscosity and decreasing solution temperature, indicating that the AIE effect is caused by the restriction of the intramolecular rotations in the aggregates of the luminogens.

An unprecedented synthesis of 8-substituted-borondipyrromethenes is described starting from 8-thiomethylbodipy 1. Aryl, heteroaryl, alkenyl, and organometallic boronic acids smoothly reacted with 1 in the presence of a catalytic amount of Pd(0) and a stoichiometric amount of Cu(I)-2-thienylcarboxylate under neutral conditions to give the corresponding Bodipy analogues in good to quantitative yields (20 examples). A remarkable reactivity was observed in some cases, e.g., ferrocenylboronic acid gave the product in 98% isolated yield after only 10 min at 55 degrees C.

A series of 14 meso-polyarylamine-BODIPY (borondipyrromethene) hybrids of the general structure A were synthesized. Two methods were used to prepare them. The first protocol involved a direct Liebeskind-Srogl cross-coupling of thiomethylbodipys 1-2 with arylaminoboronic acids (4 examples, 75-98%). The second method involves a two-step sequence: a Liebeskind-Srogl reaction to prepare 6 meso-bromoarylbodipys (58-83%) followed by a Suzuki coupling of these Br-containing BODIPYs with arylaminoboronic acids (10 examples, 44-84%). Seven of these derivatives displayed emission in the near-infrared region. The optical properties of compound 18 were rationalized in terms of its crystal structure.