We report the results of multicolour observations of 30 E/S0 galaxies with dust lanes .
For each galaxy we obtained broad-band images and narrow-band images using interference filters isolating the H \alpha + [ NII ] emission lines to derive the amount and morphology of dust and ionized gas .
To improve the wavelength coverage we retrieved data from the SDSS and 2MASS and combined these with our data .
Ionized gas is detected in 25 galaxies and shows in most cases a smooth morphology , although knots and filamentary structure are also observed in some objects .
The extended gas distribution closely follows the dust structure , with a clear correlation between the mass of both components .
An extinction law by the extragalactic dust in the dark lanes is derived and is used to estimate the dust content of the galaxies .
The derived extinction law is used to correct the measured colours for intrinsic dust extinction and the data are fitted with a stellar population synthesis model .
We find that the H \alpha emission and colours of most objects are consistent with the presence of an “ old ” stellar population ( \sim 10 Gyr ) and a small fraction of a “ young ” population ( \sim 10 - 100 Myr ) .
To check this we closely examine NGC5363 , for which archival Spitzer/IRAC and GALEX data are available , as a representative dust-lane E/S0 galaxy of the sample .