An easy design route via simple evaporation is reported for macroscopic mosaic thin films comprising the quaternary system of dl-lysine center dot HCl, poly(acrylic acid), water, and EtOH. By depositing droplets of the quaternary dispersions onto hydrophilic cover slips, the formation of macroscopic crack-free mosaic mesocrystal thin films are produced. The formation follows a multistage crystallization process, which includes the formation of a polymer-induced liquid-precursor (PILP) phase, the formation of spherulitic thin films, and the recrystallization of mosaic mesocrystal thin films. A slow cooling rate is noted to be beneficial for the mesocrystal thin films, enabling the films to be crack-free and to display low surface roughness at the nanoscale.