Chemical synthesis of natural compounds often provides useful information on their structure and properties. Synthetic imidazolones related to GFP chromophore have been a subject of extensive research. However, up to date, a few compounds corresponding to natural chromophores of red-shifted GFP-like proteins were synthesized. Model compounds that are similar but not identical to DsRed chromophore were described. It's earlier synthesized a chromophore of a non-fluorescent purple chromoprotein as FP595 .