This investigation explored aminoimidazoles from the nudibranch, Notodoris gardineri, and the sponge Leucetta sp. Five compounds were isolated and include known metabolites, clathridine (7) and its corresponding Zn complex (8), accompanied by new compounds, preclathridine A (10), clathridine B (11), and Zn-isonaamidine (12). Compounds 7, 8, 10, and 11 were isolated from the nudibrancb and 12 was obtained from the sponge. The organometallic complex 12 provides the second example of such a chemotype isolated from a sponge and this study reports the first instance of an organometallic compound isolated from a nudibranch.