Aminoxyl radicals bearing a mesogenic core

A series of aminoxyl radicals (nitronyl nitroxide or TEMPO) bearing biphenylcarbonitrile as a mesogenic core (2a–2c and 3a–3c) was prepared. Among them, unusual magnetic transition from the original Curie–Weiss phase to another magnetic phase well expressed by a singlet–triplet model was found in the 4′-undecyloxy-4-biphenylcarbonitrile derivative with oxocarbonyl-TEMPO through the thermal transition.