In some case, the starting materials are loaded onto the resin in one form, such as carboxylic acid, and cleaved in another form; a carboxamide for example. This is perfectly acceptable if the target compound requires the released function. (Peptides invariably contain a carboxylic acid or carboxamide.) However, the growth in interest in combinatorial libraries of low molecular weight non-peptides has elicited a need in new types of linker. These linkers show non-specific function after cleavage. Traceless linkers are so called because an examination of the final compound reveals no trace of the point of linkage to the solid phase.