Novel [5]radialenes with four 1,3-dithiol-2-ylidene (DT) units (2) and ethylene analogs of [5]dendralene derivatives with five DT units (3) were synthesized. Cyclic voltammetry revealed that 2 exhibited two pairs of two-electron redox processes, whereas the bis(methylthio) derivative of 3 (3a) showed a simultaneous four-electron-transfer process.