In this paper, we describe how the crystal structures of 5-benzylidenerhodanines are influenced by substituents on the phenyl ring and those of 5-cycloalkylidenerhodanines by the size of the cycloalkane ring. Although the R2/2(8) (CONH)2ring of rhodanine is generally retained in these structures, the dimers so created are associated in a wide variety of ways, often through weak interactions such as C−H···S/O, C−H···, or Br···S/O bonds. In some cases, solvent molecules present in the lattice also play a significant role in the self-organization of the crystals. [ABSTRACT FROM AUTHOR]