TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): No general preparation given. Preferred Composition: The perylene tetracarboxylic acid bisimide derivative (I) is preferably of formula (IV), (V) or (VI). The n-type semiconductor further contains laser pigment or photoconductor. Preferred Definitions:    R1-R6=monovalent substituent derived from of formula (a) or (b);    R11,R12=H, lower alkyl, or fluoro;    m=0-20;    s=0 or 1;    t=1 or 2;    n=0-30;and    L1,L2=single bond, alkylene, oxy, thio, or seleno.    SPECIFIC COMPOUNDS - 6 New perylene tetracarboxylic acid bisimide derivatives e.g. 7,18-bis(2,2,4,4,6,6-hexamethyl-3,5-dioxa-2,4,6-trisilanonan-9-yl)-7,18-diazaheptacyclo(14.6.2.22,5.03,12.04,9.013,23.020,24)hexacosa-1(23),2,4,9,11,13,15,20(24),21,25-decaene-6,8,17,19-tetrone, 7,18-bis(2,2,4,4,6,6,12,12,14,14,16,16-dodecamethyl-3,5,13,15-tetraoxa-2,4,6,12,14,16-hexasilaheptadecan-9-yl)-7,18-diazaheptacyclo(14.6.2.22,5.03,12.04,9.013,23.020,24)hexacosa-1(23),2,4,9,11,13,15,20(24),21,25-decaene-6,8,17,19-tetrone, 7,18-bis(2,2,4,4,6,6,12,12,14,14,16,16-dodecamethyl-3,5,13,15-tetraoxa-2,4,6,12,14,16-hexasilaheptadecan-9-yl)-7,18-diazaheptacyclo(14.6.2.22,5.0,12.04,9.013,23.020,24)hexacosa-1(23),2,4,9,11,13,15,20(24),21,25-decaene-6,8,17,19-tetrone, 7,18-bis(2,2,4,4,14,14,16,16-octamethyl-3,15-dioxa-2,4,14,16-tetrasilaheptadecan-9-yl)-7,18-diazaheptacyclo(14.6.2.22,5.03,12.04,9.013,23.020,24)hexacosa-1(23),2,4,9,11,13,15,20(24),21,25-decaene-6,8,17,19-tetrone, and 7,18-bis(2,2,4,4,18,18,20,20-octamethyl-3,19-dioxa-2,4,18,20-tetrasilahenicosan-11-yl)-7,18-diazaheptacyclo(14.6.2.22,5.03,12.04,9.013,23.020,24)hexacosa-1(23),2,4,9,11,13,15,20(24),21,25-decaene-6,8,17,19-tetrone are specifically claimed.    EXAMPLE - Perylene bis(allyl imide)tetracarboxylate (1.03 g) and 1,1,1,3,3,5,5-heptamethyl trisiloxane (1.53 g)were dissolved in 100 ml of toluene. Bis(1,3-bis(h2-ethenyl)-1,1,3,3-tetramethyldisiloxane)platinum was added to the reaction mixture, refluxed for 5 hours, cooled, filtered and purified using silica gel column chromatography, to obtain red powder of perylene tetracarboxylic acid bisimide derivative (I) (1.51 g) with yield of 75.3%.