Abstract A panel of penta‐coordinated, neutral organotin(IV) and organosilicon(IV) complexes of newly designed Schiff bases: 4‐(2‐hydroxymethyl‐phenylimino)‐2‐methyl‐4H‐pyran‐3‐ol ( H 2 L 1 ) and 4‐(benzothiazol‐2‐ylimino)‐2‐methyl‐4H‐pyran‐3‐ol ( HL 2 ) were synthesized and characterized using elemental analysis, spectral studies (UV/Vis, IR, 1 H, 13 C, 29 Si, 119 Sn NMR and Fluorescence) and thermal technique. Spectral studies conferred that the Schiff base act as bi/tridentate and form the penta coordinated geometry with oxygen and nitrogen donor atom (NO/NOO). The compounds were screened for in vitro antimicrobial activity using twofold serial dilution method against Gram‐positive bacteria ( Staphylococcus aureus , Bacillus cereus ), Gram‐negative bacteria ( Escherichia coli, Klebsiella pneumoniae ) and fungi ( Aspergillus niger, Candida albicans ). The antimicrobial study exposed good activity with tri‐ and di‐phenyl derivatives exhibiting excellent biological activity. Compounds 5 , 6 , 10 , 13 , 14 , 17 and 18 displayed better activity than the standard drugs. Quantitative structure activity relationship involves correlation of biological activity with the structural properties of the compounds using statistical means.