Compounds of formula (III) or (V), wherein is a solid support; L is a linking group or a single bond; T is a combinatorial unit; n is a positive integer, where if n is greater than 1, each T may be different: X is an electrophilic leaving group; Y is selected from NH-Prot, O-Prot, S-Prot, NO2, —NHOH. N3, NHR, NRR, N═NR, N(O)RR, NHSO2R, N═N═PhR, SR or SSR, where Prot represents a protecting group; A and B collectively represent a fused benzene or pyrrole ring (in either orientation), which is optionally substituted by up to respectively 4 or 2 groups independently selected from R, OH, OR, halo, nitro, amino, Me3Sn, CO2H, CO2R, R1 is a nitrogen protecting group, where if Y includes a protecting group, these protecting groups are orthogonal and R2 and R7 are independently selected from H, R, OH, OR, halo, nitro, amino, Me3Sn, and other related compounds and collections of compounds.