For a long time, luminescence phenomena were strictly distinguished between the emission of isolated molecules in dilute solutions or close‐packed structures such as in powders or aggregates. This changed with the breakthrough observation of dual‐state efficient materials, which led to a rapid boost of publications examining the influence of structural features to achieve balanced emission with disregarded molecular surroundings. Some first general structural design concepts have already been proposed based on reoccurring patterns and pivotal motifs. However, we have found another way to classify these solution and solid‐state emitters (SSSEs). Hence, this minireview aims to present an overview of published structural features of SSSEs while shining light on design concepts from a more generalized perspective. Since SSSEs are believed to bridge the gap of hitherto known aggregation‐sensitive compound classes, we hope to give future scientists a versatile tool in hand to efficiently design novel luminescent materials.

Bridging a gap: Solution and solid‐state emitters (SSSEs) combine effective emission independently from their state of aggregation. In their Minireview on page  ff., J. Voskuhl et al. describe classification of SSSEs in classic and non‐classic examples.

In this contribution, we describe a set of three chlorinated bridged ethers with varying numbers of sulfur and oxygen atoms. The substitution leads to highly emissive compounds with tunable photophysical properties in relationship to their state of aggregation, i. e. in solution, as aggregates and in the solid state. Additionally, an in-depth X-ray diffractometric analysis supported by a Hirshfeld study of non-covalent interactions and quantum chemical simulations was carried out. As the outcome, it was found that the content of sulfur in the compounds regulates the tuning of emission in solution as well as in the aggregated states as a consequence of their variation of planarity.