New substances of the type of unsymmetrical substituted biphenyls R1[MATH]R2 with R1 or R2 = n-alkyl, n-alkoxy and H-alkanoyl were synthezised. Miscibility measurements in binary systems, texture observation and comparative studies of the trends of the transition temperatures in homologous series yield a classification of the phase types. In the 4-n-alkyloxy-4'-n-alkanoylbiphenyls the smectic phase types A and E in the new variant SE, I and the variant SE, SA, I occur. The 4-n-alkyl-4'-n-hexanoylbiphenyls show the polymorphism SA, I and SB, SA, I. In the 4-n-hexyloxy-4'-n-hexylbiphenyl the new variant of polymorphism SE, SB, I exists