Two new fullerene derivatives 1a and 1b, form robust Langmuir monolayers at the air-water interface, that transfer onto substrates by Langmuir-Blodgett (LB) or Langmuir-Schaefer (LS) techniques. The measured molecular areas (105 Angstrom(2) for 1a dropped from a deuterochloform solution at 20 degrees C) reach those expected for a true monolayer of C-60 at the air-water interface. An STM image of an LS film of 1a on HOPG shows considerable order.