Approximately in 1990, we started in Riga a project on a development of a computer code for semiempirical electronic structure calculations of molecules and crystals taking into account the system symmetry. For that purpose, a quite general group-theoretical method for automatic construction of symmetry-adapted basis functions was developed [B32]. It was employed as a basis for the corresponding computer code SYM-SYM (together with Dr. A.Livshits). The program performs semiempirical (INDO) HF calculations of the electronic structure of molecules, clusters (in the Coulomb field of the surrounding crystal) and perfect crystals (using the Large Unit Cell method). It has a powerful geometry optimisation routine with Hellmann-Feynman forces (a recent development), band structure, density of states (DOS) (the method of tetrahedra), correlation correction (the electronic polaron model) among other features. The code also has a number of user-friendly shell programs. Because of the semiempirical method built into the code, the flexible geometry optimisation method and the complete exploitation of symmetry, very large systems containing hundreds of atoms can be routinely considered using comparatively small computer time and memory. The SYM-SYM code has been extensively used in a number of studies of various defects in alkali halides [B33] and corundum [B36,B40]. This software package is now being used and further developed at U.C.L.