In this work, we report the properties of Tl2InGaSe4 crystals as multifunctional material. Namely, Tl2InGaSe4 crystals are grown by the modified Bridgman method using mixtures of TlInSe2 (50%) and TlGaSe2 (50%) single crystals. The enhanced crystallization and structural stabilities are monitored by the X-ray diffraction technique during the in situ heating and cooling cycles. The structural analyses on the Tl2InGaSe4 crystals revealed domination of both of the monoclinic and tetragonal phases in the crystals. In addition, the produced crystals are used to fabricate Schottky diodes. While the scanning electron microscopy has shown that the crystals are composed of layered nanosheets, the electrical analyses have shown that the crystals exhibit light photosensitivity of 12.7 under tungsten light illumination of 10 kLuxes. The attenuation in the electrical parameters of the Ag/Tl2InGaSe4/C diodes presented by series resistance, barrier height and ideality factor upon light excitations make them promising for applications in optoelectronics as switches and photodetectors. Moreover, the alternating electrical signals analyses on the capacitance spectra displayed resonance -antiresonance oscillations in the frequency domain of 83-100 MHz. The resistance spectra also exhibited negative resistance effect in the range of 55-135 MHz. These features of the device make it suitable for use as microwave resonators and memory devices as well.