Dielectric constant (ε′) and Dielectric loss (ε″) of the binary mixtures of the pyridine and 1-propanol have been measured at microwave frequencies of X-band and J-band at 303,313 and 323K temperatures. Static dielectric permittivity (ε0) of the liquid samples has been determined using precision LCR meter. Dielectric permittivity at optical frequency (ε∞) has also been measured. Determined values of Static dielectric permittivity (ε0) and complex permittivity (ε*) at 9.1 GHz frequency were used to evaluate relaxation time (τ). Determined parameters have been interpreted in terms of molecular interaction among the molecular species of the binary mixtures.