The effects of varying halogen and solvent, in terms of vibrational and electronic properties, on the different conformers of 1-pentanamine [CH3(CH2)(4)NH2] and 1,1-dihalogeno-pentan-1-amines [CH3(CH2)(3)CX2NH2; X = F, Cl or Br] were investigated by employing the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The B3LYP functional was used with the 6-31++G(d, p) basis set. Computations were focused on the 10 conformational isomers of the compounds in the gas phase and both in non-polar (benzene) and polar (methanol) solvents. The present work explores the effects of the halogen and the medium on the conformational preference, and geometrical parameter, dipole moment, NH2 vibrational frequency, UV spectrum, highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO) orbital and DOS diagram of the conformers. The atypical characteristics of Huorine and bromine affecting the electrical bandgap, chemical hardness, electronegativity, PDOS or OPDOS plots and the absorption band are observed correspondingly. The findings of this work can be useful to those systems involving changes in the conformations analogous to the compounds studied.