Four π‐extended phosphindolizine derivatives have been newly synthesized and characterized. We express these compounds as four hayabusa (falcons) that are taking off from a nest (shown lower right), which indicates the dibenzo[b,e]phosphindolizines reported previously. We also describe the weak luminescence of one compound (shown upper left) as shining under the sun. More information can be found in the Research Article by A. Tsurusaki, K. Kamikawa, and co‐workers (DOI: 10.1002/chem.202203321). Artwork by Norifumi Kosaka of YAP Inc.

Dibenzo[b,g]phosphindolizine oxide and three types of benzo[e]naphthophosphindolizine oxides have been synthesized by the ring-closing metathesis of benzo[b]phosphole oxide and naphthophosphole oxides with two olefin tethers. Their molecular structures and properties were revealed by Xray crystallographic analysis, UV-vis spectroscopy, and electrochemical analysis. The number and position of the benzene rings were found to alter the structural geometry and the HOMO/LUMO energy levels, and their effects were investigated by theoretical calculations. Among the phosphindolizine oxide derivatives investigated, only benzo[e]naphtho[2,3b]phosphindolizine oxide with the naphthalene ring fused at 2,3-positions showed weak yellow fluorescence with a large Stokes shift.