A wide range of new oxime-based photochromic diarylethenes of the cyclopentenone series have been synthesized. Their spectral properties have been investigated in detail upon UV/vis light irradiation in acetonitrile solution, and distinct correlations between photochromic characteristics and substance structures are revealed. It was found that the introduction of an oxime group into the cyclopentene ring has a significant influence on the switching characteristics-primarily on the thermal stability, and a series of thermally stable oxime-based photochromic diarylcyclopentenones have been prepared. The results obtained suggest that the modifications of the ethene "bridge" are a promising way to tune the spectral parameters of diarylethenes in an accurate manner and thus to synthesize the photochromic compounds with desired properties.