A series of new luminescent lanthanide benzoates Ln2(phen)2(bza)4(Ac)2 {Ln = Eu (1), Gd3+(2), Tb3+ (3), Dy3+(4), Tm3+(5); phen = 1,10-phenanthroline, Hbza = benzoic acid, Ac− = acetate)} and Ln2(phen)2(bza)4(NO3)2 Ln = Sm3+(6), Eu3+ (7), Tb3+ (8), Dy3+ (9), Tm3+ (10) have been hydrothermally prepared by the usage of the π-conjugated phen ligands as chromophores. 1–5 exhibit binuclear Ln2(phen)2(bza)4(Ac)2 moieties built up from two Ln(phen)3+ groups joined together by the bridging bza− and Ac− ligands, while 6–10 show another binuclear Ln2(phen)2(bza)4(NO3)2 moieties constructed by two Ln(phen)(NO3)2+ groups linked together by the bridging bza− ligands. These compounds offer the rare examples of binuclear lanthanide benzoates decorated by phen chromophores. Luminescent and sensing properties of 1–10 were studied, revealing that europium (1 and 7) and terbium (3 and 8) benzoates can be used as a bifunctional luminescent probe for acetone and Fe3+ with high efficiency and selectivity. This work offers the only example of luminescent lanthanide benzoates incorporating phen chromophores and small auxiliary π-conjugated NO3− ligands, whose europium benzoate shows good bifunctional sensor targeted for acetone and Fe3+ ion. Display omitted •A series of new luminescent lanthanide benzoates were hydrothermally prepared.•The Eu3+ and Tb3+ complexes shows bifunctional sensor for acetone and Fe3+ ion.•5–6 offer the rare examples of lanthanide benzoates incorporating phen chromophores.