[3] On 16 March 1838, Dillwyn married de la Beche's daughter Elizabeth and, with his wife's artistic guidance, the pottery produced a range of beautiful Etruscan ware which is today a collector's item.

He was head of the firm of Dillwyn and Richards at the Landore spelter works and began to expand his industrial activities to include silver refining.

In the 1880s, following a slump in the steel industry, Dillwyn concentrated his manufacturing activities on his spelter works at Llansamlet (equally in the built-up area of Swansea), and soon became one of the major zinc producers in the country.

Dillwyn promoted the new piped supply of pure water to the town, agreed to the mass naming and renaming of streets and their improvement through the introduction of paving.

In Parliament, Dillwyn had built a reputation by the 1860s as an advanced radical and, at least until the election of men such as Henry Richard, he was regarded as the leader of the Welsh Liberal Party from his regular corner seat below the gangway.

He introduced bills in 1860 and 1863 to enable dissenters to be elected as trustees of endowed schools and his motion on the Church of Ireland (28 March 1865) influenced Gladstone's gradual move towards disestablishment.

During the passage of the Second Reform Bill Dillwyn's involvement as a leading member of the 'Tea Room' cabal of disaffected Liberals in April 1867 helped to bring about household suffrage, a measure which led to an overnight increase in the urban electorate throughout Great Britain.

[12] Dillwyn's slashed majority demonstrated that the now marginal political status locally, heightened by the Swansea Town seat excluding most of the overwhelmingly working-class suburbs and contributory boroughs.

Dillwyn, together with James Motley, a fellow member of the RISW, published an illustrated volume, intended as first of a series, on the natural history of Labuan.

[14] Within the field of ornithology Dillwyn also named the bird species Megapodius cumingii (Philippine megapode)[15] and Copsychus stricklandii (White-crowned shama).

On 1 June a general meeting of the Swansea Conservatives and Liberal Unionists, allied against the Irish Home Rule movement, resolved to nominate F.

[17] On 18 June he attended a meeting at Swansea Liberal Club where David Randell was re-adopted as candidate for the Gower constituency and gave speech.