In this paper we show the utility of H-1/C-13/Si-29 triple resonance, 3D, and pulse field gradient (PFG) NMR techniques for characterizing organosilicon based polymers. The dendrimers studied are first generation Si(CH2CH2SiHMe2)(4) and second generation Si[CH2CH2SiMe(CH2CH2SiHMe2)(2)](4) polycarbosilanes. The signals from one-bond and two-bond connectivities among H-1 atoms coupled to both C-13 and Si-29 at natural abundance have been selectively detected. The spectral dispersion and the atomic connectivity information present in the 3D NMR spectra provide resonance assignments and a definitive structure proof.