These results indicate that spontaneous resolution occurs during the crystallization of 2a, thus representing a rare example of conglomerate formation. The strain energy of 2a was estimated to be 15.5 kcal mol -1 using DFT calculations at the B3LYP/6-31G(d) level based on a hypothetical homodesmotic reaction (Fig. ). The activation barrier of the racemization of 2a was evaluated by monitoring the decrease in the circular dichroism The UV/vis absorption of CBBC 2a in the 300-380 nm range is stronger than the absorption corresponding to the n-π* transition in benzophenone. This is due to the contribution of the π-π* transition in 2a that arises from the π-extension along the biphenyl subunits (Fig. ). While 2a is virtually non-emissive in CH2Cl2 at room temperature, it exhibits phosphorescence with a lifetime of 1.3 × 10 2 ms in 2methyltetrahydrofuran (2-MeTHF) at 77 K (Fig. ). Transient absorption spectroscopy measurements indicated that intersystem crossing (ISC) proceeds rapidly with a time constant of 3 ps (Fig. ). The CD and circularly polarized phosphorescence (CP-Phos) spectra of (M,M)-2a and (P,P)-2a are shown in Fig. . The |g| value of CP-Phos reaches 3.3 × 10 -2 at 447 nm, which is higher than those of previously reported chiral organic phosphors . 2,7,10,15-Tetra(p-tolyl)CBBC 2j, which was synthesized via the Suzuki-Miyaura cross-coupling reaction of 2h with 4-methylphenylboronic acid, exhibited fluorescence at 482 nm in CH2Cl2 with a quantum yield of 3.7% and a lifetime of 6.4 ns (Fig. ). Its enantiomers display intense circularly polarized fluorescence (CP-Flu) with a high |g| value of 1.4 × 10 -2 (Fig. ), which is comparable to those of previously reported efficient organic CP-Flu emitters . TD-DFT calculations of 2j revealed that their electric and magnetic transition dipole moments adopt parallel arrangements due to their D2-symmetric structures (22-24) (Fig. ). These results demonstrate that CBBC is an ideal skeleton for CPL-active materials.