Nonlinear optical (NLO) crystal, which simultaneously exhibits strong second‐harmonic‐generation (SHG) response and desired optical anisotropy, is a core optical material accessible to the modern optoelectronics. Accompanied by strong SHG effect in a NLO crystal, a contradictory problem of overlarge birefringence is ignored, leading to low frequency doubling efficiency and poor beam quality. Herein, a series of rare earth cyanurates RE5(C3N3O3)(OH)12 (RE=Y, Yb, Lu) were successfully characterized by 3D electron diffraction technique. Based on a “three birds with one stone” strategy, they enable the simultaneous fulfillment of strong SHG responses (2.5–4.2× KH2PO4), short UV cutoff (ca. 220 nm) and applicable birefringence (ca. 0.15 at 800 nm) by the introduction of rare earth coordination control of π‐conjugated (C3N3O3)3− anions. These findings provide high‐performance short‐wavelength NLO materials and highlight the exploration of cyanurates as a new research area.

Carbon nanotubes (CNTs) exhibit excellent mechanical, electrical, thermal, and chemical properties and show promising application potentials in numerous fields. Among different types of CNTs, vertically aligned CNT arrays (VACNTs) exhibit more superiors due to their good alignment, controllable structures and morphologies, and easy mass‐production, and so forth. During the past years, extensive efforts were put into the controlled synthesis of VACNTs with desired structures and morphologies. Among these efforts, it should be noted that, it is of significant importance to improve the array lengths of VACNTs, especially for the fabrication of VACNTs‐based fibers, transparent flexible films, and other functional materials, and so forth. However, it still remains a big challenge to synthesize VACNTs with length over centimeters. In this review, we summarize the growth mechanism, kinetics, growth factors of VACNTs, and the strategies for how to improve their array lengths. Finally, we also propose our outlook on the future development of VACNTs.

Nonlinear optical (NLO) crystal, which simultaneously exhibits strong second‐harmonic‐generation (SHG) response and desired optical anisotropy, is a core optical material accessible to the modern optoelectronics. Accompanied by strong SHG effect in a NLO crystal, a contradictory problem of overlarge birefringence is ignored, leading to low frequency doubling efficiency and poor beam quality. Herein, a series of rare earth cyanurates RE5(C3N3O3)(OH)12 (RE=Y, Yb, Lu) were successfully characterized by 3D electron diffraction technique. Based on a “three birds with one stone” strategy, they enable the simultaneous fulfillment of strong SHG responses (2.5–4.2× KH2PO4), short UV cutoff (ca. 220 nm) and applicable birefringence (ca. 0.15 at 800 nm) by the introduction of rare earth coordination control of π‐conjugated (C3N3O3)3− anions. These findings provide high‐performance short‐wavelength NLO materials and highlight the exploration of cyanurates as a new research area.

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