Chromium, 2-hydroxy-3,5-dinitrobenzenediazonium-4(or 5)-hydroxy-1-naphthalenesulfonic acid coupling products 3-hydroxy-4-[(1-hydroxy-2-naphthalenyl)azo]-1-naphthalenesulfonate complexes, compds. with N,N'-bis(Ph and o-tolyl and xylyl)guanidine [91697-12-0