Single crystals of the diacetylene derivatives ETCD, 4BCMU, IPUDO, and DCH were polymerized by repeated irradiation with single pulses of 3 MeV electrons. The conductivity induced by these pulses was determined as a function of the accumulated dose. At low doses the transient radiation-induced conductivity increases due to the production of polymer chains, on which the charge carriers are highly mobile. For low accumulated radiation dose the charge carrier mobility is found to be of the order of 1 cm(2)/(V s). For higher accumulated dose the lifetime of the charge carriers toward trapping as well as their mobility decrease. For accumulated radiation doses that are conventionally used to produce polydiacetylenes, the charge carrier mobility has decreased by approximately 1 order of magnitude.