High-resolution measurements of the molar volume, V, measured as a function of temperature at two different pressures allowed the calculation of the isobaric thermal expansion coefficient, alpha(p)(T), and isothermal compressibility coefficient, beta(T)(T). Critical exponents for observed singularities in both thermodynamic quantities were found. It was confirmed that the same critical exponent a, usually assigned to heat capacity, describes singularities of the thermal expansion and the isothermal compressibility coefficients. Two compounds from the two different homologous series, nCB and (m) over bar S5, were studied. V(T) and beta(T)(T) variations in 8CB showed a continuous phase transition with the effective critical exponent a = alpha’ = 0.32 +/- 0.02. For 10S5 a weakly first-order transition with a volume jump Delta V = 0.127 +/- 0.001 cm(3)/mol (Delta V/V = 2.6 x 10(-4))was observed and an exponent a = alpha’ = 0.50 +/- 0.02 was found.