An efficient method is described for the synthesis of 9-phenyl-9H-pyrido[3,4-b]indole and 9-(4-chlorophenyl)-9H-pyrido[3,4-b]indole by employing a catalytic amount of CuI (10 mole%) without any ligand. The single crystal of 9-phenyl-9H-pyrido[3,4-b]indole was produced by crystallization from hexane and ethyl acetate mixture that was investigated by single X-ray diffraction (XRD). The compound crystallizes in monoclinic P21/c space group with unit cell dimensions a = 11.3132(5) angstrom, b = 12.0061(5) angstrom, c = 9.2498(4) angstrom, alpha = 90 degrees, beta = 103.187(3)degrees, gamma = 90 degrees. H-1 and C-13 NMR, IR, and mass spectroscopic methods of the compounds are also discussed.