Short-step synthesis and chiroptical properties of polyaza[5]-[9]helicenes with blue to green-colour emission.

We have developed a two- or three-step synthesis of polyaza[5]-[9]helicenes by consecutive N-H/C-H coupling with a hypervalent iodine reagent. We further evaluated their photophysical properties, and circularly polarized luminescence properties and found that g values increase with the number of fused rings up to 2.7 × 10, which is the highest value among [9]helicenes.