Ab initio Hartree-Fock, MP2, and Becke 3-Lee-Yang-Parr (B3LYP) density functional theory calculations using 6-31G*, 6-311G**, and 6-311G(2df,p) basis sets were carried out to study molecular structures and vibrational spectra of pyrrole and carbazole. We report the results of the molecular structures and fundamental vibrational frequencies obtained on the basis of the calculations. The assignments of frequencies show a one-to-one correspondence between the observed and calculated fundamentals.