The first observations of the 2(20)-2(11) transition of cyclopropenylidene (C3H2) at 21.6 GHz are described. In all cases where it has been detected, the line appears in absorption, showing that this transition is "refrigerated" (i.e., Tex < 2.7 K) in cold dust clouds. These results are compared with those for the 1(10)-1(01) transition of C3H2, and the consequences for the excitation of C3H2 qualitatively discussed.