Both calculations and experimental data, showing the possibility of formation Of I-3(-), I2Cl-, and ICl2- anions through IC reduction processes, are described in detail. The above processes were used successfully for the preparation of different molecular conductors based on trihalide anions and bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF). The reaction between ICl and BEDT-TTF occurring in a strong polar reaction media (epsilon >= 34.8 D) results in the formation of novel molecular conductors containing different sets of the I-3(-), I2Cl-, and ICl2- anions: beta-(BEDT-TTF)(2)[(I-3)(0.4)(I2Cl)(0.6)], beta'-(BEDT-TTF)(2)[(I2Cl)(0.2)(ICl2)(0.8)], and beta"-(BEDT-TTF)2[(I-3)0.075(I2Cl)0.150(ICl2)0.775]. These molecular conductors reveal semiconducting (beta'-phase) as well as metallic (beta- and beta"-phases) transport properties. It is also shown that in the reaction media with polarity less than 18.4 D only the I-3(-) anion is incorporated in the BEDT-TTF-based molecular crystals. This fact is an unexpected outcome of our study.