Jiang, S., Zhao, S., Yang, Y., Guo, J., Zhao, W., Wang, X., Wu, L., Chen, L. (2026). Anion Size‐Dependent Conformational Folding of Guanidinopropionate: Enabling Tunable Birefringence and Balanced Second‐Harmonic Generation Performance. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.3114156