The relaxation properties of macromolecules present problems which require modification of existing experimental procedures for 2D heteronuclear cross-correlation NMR of small molecules. In macromolecules, the large 1H linewidths for hydrogens bound directly to 13C strongly limit achievable resolution for correlations over one bond. For correlations utilizing nJ, n > 1, resolution is improved at the expense of sensitivity, but explicit consideration must be given to the effect of transverse relaxation on the efficiency of heteronuclear magnetization transfer. For macromolecules with correlation times in the spin-diffusion regime, long-range correlations were obtained via 1H1H cross relaxation followed by transfer to 13C. This experiment shows improved resolution and sensitivity, permits the observation of 1H1H cross relaxation in some magnetically equivalent spin systems and may be useful for indirect detection of 1H1H cross relaxation in crowded 1H NMR spectra.