diff --git a/schemas/ispyb/updates/2025_05_23_Ligand_and_junction_tables.sql b/schemas/ispyb/updates/2025_05_23_Ligand_and_junction_tables.sql
new file mode 100644
index 0000000..f62fade
--- /dev/null
+++ b/schemas/ispyb/updates/2025_05_23_Ligand_and_junction_tables.sql
@@ -0,0 +1,58 @@
+-- To undo:
+-- drop table BLSample_has_Ligand;
+-- drop table Ligand_has_PDB
+-- drop table Ligand;
+-- delete from SchemaStatus where scriptName = '2025_05_23_Ligand_and_junction_tables.sql';
+
+
+INSERT IGNORE INTO SchemaStatus (scriptName, schemaStatus) VALUES ('2025_05_23_Ligand_and_junction_tables.sql', 'ONGOING');
+
+CREATE TABLE Ligand (
+    ligandId int(11) unsigned PRIMARY KEY AUTO_INCREMENT,
+    proposalId int(10) unsigned NOT NULL COMMENT 'References Proposal table',
+    name varchar(30) NOT NULL COMMENT 'Ligand name',
+    SMILES varchar(400) COMMENT 'Chemical structure',
+    libraryName varchar(30) COMMENT 'Name of ligand library, to preserve provenance',
+    libraryBatchNumber varchar(30) COMMENT 'Batch number of library, to preserve provenance',
+    plateBarcode varchar(30) COMMENT 'Specific barcode of the plate it came from, to preserve provenance',
+    sourceWell varchar(30) COMMENT 'Location within that plate, to preserve provenance',
+    CONSTRAINT `Ligand_fk_proposalId`
+      FOREIGN KEY (proposalId)
+        REFERENCES Proposal (proposalId)
+          ON DELETE CASCADE
+          ON UPDATE CASCADE
+) COMMENT = 'Ligands in biochemistry are substances that bind to biomolecules';
+
+CREATE TABLE BLSample_has_Ligand (
+    blSampleId int(10) unsigned,
+    ligandId int(11) unsigned,
+    PRIMARY KEY (blSampleId, ligandId),
+    CONSTRAINT BLSample_has_Ligand_fk1
+      FOREIGN KEY (blSampleId)
+        REFERENCES BLSample (blSampleId)
+          ON DELETE CASCADE
+          ON UPDATE CASCADE,
+    CONSTRAINT BLSample_has_Ligand_fk2
+      FOREIGN KEY (ligandId)
+        REFERENCES Ligand (ligandId)
+          ON DELETE CASCADE
+          ON UPDATE CASCADE
+) COMMENT = 'Junction table for BLSample and Ligand';
+
+CREATE TABLE Ligand_has_PDB (
+  ligandId int(11) unsigned,
+  pdbId int(11) unsigned,
+  PRIMARY KEY (ligandId, pdbId),
+  CONSTRAINT Ligand_Has_PDB_fk1
+    FOREIGN KEY (ligandId)
+      REFERENCES Ligand (ligandId)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+  CONSTRAINT Ligand_Has_PDB_fk2
+    FOREIGN KEY (pdbid)
+      REFERENCES PDB (pdbId)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE
+) COMMENT = 'Junction table for Ligand and PDB';
+
+UPDATE SchemaStatus SET schemaStatus = 'DONE' WHERE scriptName = '2025_05_23_Ligand_and_junction_tables.sql';