The films aligned by drawing thin lyotropic liquid crystal layers of benzopurpurin-4B were investigated by X-ray and electron diffraction methods. The analysis of diffraction data was carried out by straigh-forward (Patterson synthesis) and model procedures. The film structure is crystalline on the microlevel. Molecules ar packed in monoclinic lattice (a=27A, b=7. 2Å, c=59.5Å, β =141°) corresponding to space group C2/c. This model explains the type geometry of molecular aggregates in the lyotropic liquid crystal phase of benzopurpurin-4B.