The variation of density with temperature in four compounds, N-(p-n-octyloxybenzylidene)-p-n-alkylanilines, 8O.Om's, viz. N-(p-n-octyloxybenzylidene)-p-n-propoxyaniline, 8O.O3, N-(p-n-octyloxybenzylidene)-p-n-butylaniline, 8O.O4, N-(p-n-octyloxybenzylidene)-p-n-hexylaniline, 8O.O6, and N-(p-n-octyloxybenzylidene)-p-n-heptylaniline, 8O.O7, is presented. The density and thermal expansion coefficient results reveal that the phase transitions present in these compounds are of first order. Using the thermal expansion coefficient, the temperature dependence of a number of thermodynamical (thermoacoustic and anharmonic) parameters of these compounds are estimated. These results reveal that all the parameters show characteristic change in the vicinity of the phase transformation. The results are discussed in light of the body of data available.