Cocrystals may be characterized in a wide variety of ways.  Powder X-Ray diffraction proves to be the most commonly used method in order to characterize cocrystals.  It is easily seen that a unique compound is formed and if it could possibly be a cocrystal or not owing to each compound having its own distinct powder diffractogram.  Single-crystal X-ray diffraction may prove difficult on some cocrystals, especially those formed through grinding, as this method more often than not provides powders.  However, these forms may be formed often through other methodologies in order to afford single crystals.
Aside from common spectroscopic methods such as FT-IR and Raman spectroscopy, solid state NMR spectroscopy allows differentiation of chiral and racemic cocrystals of similar structure.
Other physical methods of characterization may be employed.  Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are two commonly used methods in order to determine melting points, phase transitions, and enthalpic factors which can be compared to each individual cocrystal former.