V(TCNE)x·y(MeCN) is a molecule-based magnet with Tcvarying from ∼ 80 to ∼ 150K depending on the preparation. The electron spin resonance properties are reported for a preparation with Tc≈ 82 K. The temperature dependence of the ESR integrated intensities, linewidths and resonance field have been measured over the range from 3 to 300 K. Above ∼ 150 K the linewidth increases linearly consistent with thermal broadening. Near Tcan anomalous minimum in the linewidth is observed which we attribute to critical behavior associated with the dipolar interaction as described by Huber and the presence of disorder. At low temperatures a resonance field shift and excess linewidth are observed to be consistent with the theory of Becker for spin glasses with anisotropy and zero remnant magnetization.