Highly Stable Eu(III) and Tb(III) Complexes Based on Triarylborane‐Functionalized Cyclen Derivatives as Visual Temperature Probes and White‐Light Emitters

New and highly stable Eu(III) and Tb(III) complexes based on two triarylborane functionalized cyclen derivative ligands L1 and L2, have been achieved. The Eu(III) and Tb(III) lanthanide compounds have been found to display highly distinct and contrasting temperature‐dependent dual emission and decay lifetimes, rendering them as potential sensitive temperature probes. The emission colors of the new lanthanide complexes can be tuned by controlling the ratio of the Eu(III) and Tb(III) complexes in a binary composite and the temperature. Bright white light emission based on the new binary Eu(III) and Tb(III) complexes has been achieved. Furthermore, the triarylborane functionality of the new complexes enables their use as effective probes for anions such as fluoride ions, allowing the further tuning of the lanthanide emission.