The x-ray crystal structure of thermally sensitive 3,3'-bicyclopropenyl (1) (mp 198 K) has been detd. at 103 K using a miniature-zone melting procedure with focused IR light. The structural parameters calcd. for the anti conformer using the Hartree-Fock SCF procedure with a 3-21G basis set compare well with the exptl. data. The photoelectron spectrum of 1, which exhibits three peaks of different heights well sepd. from a smaller fourth one, can be interpreted in terms of about a 2:1 mixt. of anti and gauche conformers, resp., in the gas phase.