We have used a cavity perturbation technique to probe the electrodynamic response of various low-dimensional molecular metals in high magnetic fields. We discuss some of the technical aspects of these measurements and go on to present recent experimental data obtained in magnetic fields of up to 33 T. In addition to providing finite frequency information in this frequency range, which is highly relevant to narrow bandwidth conducting systems, we show how the extreme flexibility and sensitivity of this technique offers great potential for probing the properties of novel materials in high magnetic fields. © 1998 Elsevier Science B.V. All rights reserved.