This paper describes the evaluation of [(R)-2-Amino-3-(4-isothiocyanatophenyl)propyl]-trans-(S,S)-cyclohexane-1,2-diamine-pentaacetic acid (CHX-A’’-DTPA-NCS) and 2-S-(4-isothiocyanatobenzyl)−1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA-NCS) as bifunctional chelators for ¹⁷⁷Lu. While ¹⁷⁷Lu-CHX-A’’-DTPA-NCS could be obtained in high yields at equimolar ratios of lutetium to CHX-A’’-DTPA-NCS,>95% yield of ¹⁷⁷Lu-NOTA-NCS could be achieved at 1:2 M ratio of lutetium to NOTA-NCS. Trace metals reduced the yields of ¹⁷⁷Lu-NOTA-NCS significantly as compared to ¹⁷⁷Lu-CHX-A’’-DTPA-NCS. In vitro stability of ¹⁷⁷Lu-CHX-A’’-DTPA-NCS was also superior to 177Lu-NOTA-NCS. It could be concluded from this study that among the two chelators evaluated, CHX-A’’-DTPA-NCS is more appropriate for preparation of ¹⁷⁷Lu radiopharmaceuticals.