L1, L2 and L {HEAD ~ each} independently represent {TAIL ~ the single bond}, a substituted or unsubstituted arylene group having 6 to 60 nuclear carbon atoms, a substituted or unsubstituted heteroarylene group having 3 to 60 nuclear carbon atoms or a substituted or unsubstituted fluorenylene group 
independently represent
L1 , L2 and L { HEAD ~ each } independently represent { TAIL ~ the single bond } , a substituted or unsubstituted arylene group having 6 to 60 nuclear carbon atoms , a substituted or unsubstituted heteroarylene group having 3 to 60 nuclear carbon atoms or a substituted or unsubstituted fluorenylene group
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH