The solid phase behavior of a series of monosubstituted F-, Cl-, Br-, I-, and CH3- and two 2,4-halogen-disubstituted 2-hydroxy-2-phenylacetic acid (mandelic acid) derivatives was investigated. The study includes detailed information about melting temperature, melting enthalpy, Xray diffraction data, as well as selected binary phase diagrams of the respective chiral systems. Aside from the known metastable metastable conglomerates was found.