About the molecular interactions between molecules. Kirkwood correlation factor g was also calculated to gain information In this paper precisely measured values of static permittivity (ε0 ) and permittivity at optical frequency (ε ∞) of the binary mixtures of bromobenzene (BB) and 1- heptanol (1- HeOH) of varying concentration at 303 0C are reported. ε0 and ε∞ were found to deviate from ideal behavior with concentration variation. The excess static permittivity was calculated from measured data. The character change of ε0 is presented by its excess value as a function of composition of mixture. The excess property was qualitatively analyzed to gain valuable information regarding orientation of electric dipoles in polar liquids. Earlier reported results of the binary mixtures of BB + MeOH (methanol), BB + 1-PrOH (1-propanol) and BB + 1-BuOH (1-butanol) are compared with the data of BB + 1-HeOH. Effect of increase in chain length of primary alcohol on the dielectric properties of the mixtures of BB + alcohol is discussed. Measured static permittivity and refractive index data of BB + 1-HeOH mixtures are also compared with those estimated by different mixing rules.