Vapour pressures as a function of temperature for the three isomorphous crystalline substances 1-bromo-4-chlorobenzene [CA 106-39-8], 1-chloro-4-iodobenzene [CA 637-87-6], and 1-bromo-4-iodobenzene [CA 589-87-7] were determined using a diaphragm manometer and torsion mass-loss effusion. An unconventional but simple method is used for the representation and the assessment of the experimental results. The method, which is illustrated with literature data sets on liquid water and crystalline trans-diphenylethene, is physical in nature and at the same time reveals the quality of the experimental data in terms of random and systematic errors. The thermodynamic sublimation properties at T = 298.15 K were evaluated, the results being : for 1-bromo-4-chlorobenzene, Delta(cr)(g) G(m)degrees = -9062 J.mol(-1), Delta(cr)(g)H(m)degrees = 69.34 kJ.mol(-1), Delta(cr)(g)C(p,m)degrees = -67 J.K-1.mol(-1); for 1-chloro-4-iodobenzene, Delta(cr)(g)G(m)degrees = -6309 J.mol(-1), Delta(cr)(g)H(m)degrees = 71.86 kJ.mol(-1), Delta(cr)(g)C(p,m)degrees = -79 J.K(-1.)mol(-1;) and for 1-bromo-4-iodobenzene, Delta(cr)(g)G(m degrees) = -1497 J.mol(-1), Delta(cr)(g)H(m)degrees = 78.53 kJ.mol(-1), 0.4 kJ.mol(-1), and 25 J.K-1.mol(-1) in Delta(cr)(g)G(m)degrees, Delta(cr)(g)H(m)degrees, and Delta(cr)(g)C(p,m)degrees, respectively.