Many of us get used to observing the same appearance for each compound, but the nature of fluorescent dyes and especially Cyanine dyes is a complicated one.
As a good example, we can show up some photos of non-sulfonated Cyanine5 dye NHS ester looking like a blue liquid in solution, but in the solid state, it can be something in-between golden powder and dark brown crystals depending on the drying method and the solvent used during the production phase. For your reference, please see the examples of solution in MeCN with a concentration of 1 mg/mL and related solid forms prepared according to different drying protocols.
