Thin film solar cells based on earth-abundant and environmentally friendly Cu2ZnSn(S,Se)4 absorbers are a very promising technology reaching the efficiency of 12.6 %. However, the performance of these solar cells needs to be improved in order to reach higher efficiencies. One of the keys to get a high efficiency in the familiar Cu(In,Ga)(S,Se)2 devices was the optimization of the absorber band gap coupling with the solar spectrum implementing the band gap engineering. Cu2Zn(Sn,Ge)(S,Se)4 (CZTGSSe) solid solution are a promising candidate to achieve this band gap engineering. The system shows a continuous band gap tuning from the 1 to 2.3 eV change the ratio of the cations [Ge]/([Sn] + [Ge]) and/or [Se]/([S]+[Se]). Additional potential of this solid solution system is to produce multi-junction devices to optimize photovoltaic conversion improving the device efficiency in different spectral regions. However, the efficiency improvement of the devices based on such a complex compounds could be achieved only based on the study of their fundamental properties and developing the fast methods for their quality control.   Raman scattering study of different materials showed it high potential for the fast and nondestructive characterization of the structure, composition, defect concentration and secondary phases presence [1-3]. Nevertheless, all the mentioned parameters could be obtained only using some reference Raman spectra obtained in the high quality samples. For this purpose single crystals of solid solutions of Cu2Zn(Sn,Ge)S4 (CZTGS) and Cu2Zn(Sn,Ge)Se4 (CZTGSe) were grown by chemical vapour transport, covering the whole range from pure Sn to pure Ge content compounds. Vibrational properties of the grown samples were studied by Raman spectroscopy in resonant and non-resonant conditions under different excitation wavelength (532, 633 and 785 nm). The systematic analysis has allowed to describe with high accuracy the evolution of the Raman modes with the [Ge]/([Sn] + [Ge]) ratio modification. All the peaks shifted to highest wavenumbers when increasing the [Ge]/([Ge] + [Sn]) ratio. A linear model has been proposed to relate the change of [Ge]/([Ge] + [Sn]) ratio to the Raman shift of the main peak. In selenium containing compounds, all A symmetry peaks exhibited only one mode behavior. In the case of sulfur containing compounds, most of the peaks showed a two mode behavior, including two A symmetry modes. Some preferential occupation of Sn and Ge atoms in CZTGS, as well as mass differences between anions in CZTGS and CZTGSe solutions, could be reasons of found mode befaviour in the analyzed samples.   This work was supported by the Marie Curie-IRSES project (PVICOKEST, GA: 269167). MG acknowledges the STCU 5985 and Institutional CSSDT 15.817.02.04A projects.