Two bulky hydroxy-isopropyl substituents on the quadricyclane 2 generate a compression of the intramolecular hydrogen bond (014...015 2.687 angstrom) and a lengthening of the C1-C5 bond (1.573 angstrom) of the four membered ring. The corresponding values of the bis(hydroxymethyl) derivative 1 are 010...011 2.799 angstrom and C1-C5 1.546 angstrom), respectively.